Aortic arch filtration system for carotid artery protection

ABSTRACT

Filtration systems with integrated filter element(s) forming portions of the wall of the filtration catheter are disclosed. The filtration catheters disclosed herein are designed to be used alone or in conjunction with another filter device to provide embolic protection of both carotid arteries. Occlusive element such as balloon is placed on the exterior of the filtration catheter to redirect blood flow in the vessels during the filtration process as well as to help anchor the filtration catheter inside the vessel. The integrated filter element(s) does not require collapsing thus significantly reduces the complexity of the filtration system retrieval process and the chances of releasing emboli back into the blood stream. The compact design of the filtration systems makes them particularly suitable for embolic protection during endovascular procedures on or close to the heart.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. provisional patent application61/587,413 filed on Jan. 17, 2012 to Ganesan et al., entitled “AorticArch Filter Structure for Carotid Artery Protection” and U.S.provisional patent application 61/661,643 filed on Jun. 19, 2012 toGanesan et al., entitled “Aortic Arch Filtration Catheter for CarotidArtery Protection,” both of which are incorporated herein by reference.

FIELD OF THE INVENTION

The inventions, in general, are related to embolic protection devicesfor inhibiting emboli from entering the carotid arteries from the aorta.The inventions are further related to filtration systems with acomponent that extends from the brachiocephalic artery to the leftcarotid artery along the aortic arch to filter flow from the aorta. Theinvention also relates to methods for use of such filtration systems,such as during procedures on the heart that can generate emboli at theaortic arch.

BACKGROUND

Less invasive procedures can provide desirable medical results withreduced recovery time and reduced risk to the patient. Thus, manysurgical procedures are performed using endoscopes or the like inpercutaneous formats. A large number of less invasive procedures withinthe cardiovascular system are now commonly performed, such asangiograms, angioplasty procedures and stent delivery procedures.

Endovascular procedures on or in the vicinity of the heart can create arisk of emboli generation in the aorta near the heart. Other procedureson the heart may also generate emboli along the ascending aorta. Emboliin the ascending aorta can enter the carotid arteries along the aorticarch, and emboli in the coronary arteries can travel to the brain andcause a stroke. Heart valve prostheses have been successfully used toreplace damaged natural heart valves that no longer perform theirfunctions in a satisfactory way. Commercial heart valve prosthesesinclude both mechanical valves with rigid occluders and tissue-basedprostheses with flexible leaflets. These valves have been implantedsurgically through the chest with the patient on cardiopulmonary bypass.Prosthetic heart valves have been developed for percutaneous orendovascular delivery, such as the Sapien™ aortic heart valve prosthesisfrom Edwards Lifesciences. While endovascular procedures aresignificantly less invasive to the patient than procedures through thechest wall, these procedures can create risk from emboli within theaortic root that can travel to the brain and cause strokes. Ghanem etal. for example discussed embolization during transcatheter aortic-valveimplantation procedure in an articled in Journal of American College ofCardiology Vol. 55, No. 14, 2010, pg. 1427-1432 entitled “Risk and Fateof Cerebral Embolism After Transfemoral Aortic Valve Implantation,”incorporated herein by reference.

SUMMARY OF THE INVENTION

In a first aspect, the invention pertains to a biocompatible filtrationcatheter. The catheter can comprise a shaft having a proximal end and adistal end with a distal opening; an integrated filter elementintegrated as part of a wall of the shaft at or near the distal end ofthe shaft, wherein the integrated filter element provides for fluid flowout from the interior of the catheter; a distal section extending in adistal orientation from the integrated filter element; an occlusiveelement associated with the exterior of the distal section at or nearthe distal end of the catheter that can extend radially outward from theexterior of and around the circumference of the shaft; and a conduitextending within the shaft from the distal end through at least thedistal section to the integrated filter element to provide fluidcommunication between the distal opening and the integrated filterelement. In some embodiments, the integrated filter element of thefiltration catheter comprises interwoven fibers. The interwoven fibersof the filter element can further comprise metal filaments and/orsurface capillary fibers. The integrated filter element generally has alength from about 10 mm to about 70 mm and effective pore sizes of about50 micron to about 500 micron. The integrated filter element generallycomprises approximately the same outer diameter as the shaft of thefiltration catheter. In some embodiments, the occlusive element of thefiltration catheter is a balloon, which has an extended configurationwith a diameter suitable to occlude a human brachiocephalic artery. Insome embodiments, the balloon comprises a compliant deformable materialconnected to an exterior surface of the distal section to provide forinflation of the balloon. The shaft of the filtration catheter cancomprise a balloon lumen to provide fluid communication between aproximal port and the interior of the balloon. In one embodiment, thefiltration catheter has a diameter between about 5 Fr to about 7 Fr. Insome embodiments, the filtration catheter can further comprise a sheathslidably positioned over the catheter having a configuration extended ina distal direction relative to the catheter covering the integratedfilter element.

In a second aspect, the invention pertains to a filtration system. Thefiltration system can comprise a filtration catheter described hereinand a filter device that comprises a guide structure and an independentfilter element supported by the guide structure. In general, thefiltration catheter comprises a central lumen that is suitable for thedelivery of the independent filter element mounted on the guidestructure through the distal opening of the shaft. In some embodiments,the independent filter element of the filter device comprises surfacecapillary fibers (SCF fiber filter element) having a first configurationin a bundle with a low profile and an extended configuration with thecenters of the fibers flaring outward from the guide structure. Theguide structure used for SCF fiber filter element can comprise acorewire and an overtube with the corewire extending through a lumen ofthe overtube. The relative movement of the corewire and the overtubetransitions the SCF fibers from the low profile configuration to theextended configuration. In some embodiments, the independent filterelement of the filter device comprises a filter basket. The filterbasket in some embodiments can comprise an opening into the filterbasket oriented toward the proximal end of the guide structure. In someembodiment, the filtration system described herein further comprises anaspiration catheter with dimension providing for placement over theguide structure of the filter device and delivery through the lumen ofthe filtration catheter.

In a third aspect, the invention pertains to a method for providingembolic protection during an endovascular procedure on or near apatient's heart using a filtration system described herein. Thefiltration system comprises a filtration catheter that comprises a shaftwith an inflow opening and a flow conduit, a first integrated filterelement replacing a portion of the shaft and an occlusive element distalto the integrated filter element and proximal to the inflow opening withthe flow conduit extending from the inflow opening to the integratedfilter element. The embolic protection method comprises delivering thefiltration catheter through the right subclavian artery to position theocclusive element in the brachiocephalic artery and deploying theocclusive element to redirect blood to enter the inflow opening, flowthrough the flow conduit, and exit as filtered flow through the firstintegrated filter element into the brachiocephalic artery, bypassing theocclusive element. In embodiments where the filtration cathetercomprises a second integrated filter element and a second occlusiveelement distal to the first integrated filter element and proximal tothe second integrated filter element with a distal flow conduitproviding fluid communication between the inflow opening and the secondintegrated filter element past the second occlusive element, delivery ofthe catheter positions the second occlusive element within the leftcarotid artery, and the embolic protection method further comprisesdeploying the second occlusive element to redirect blood to enter theinflow opening, flow through the conduit, and exit as filtered flowthrough the second integrated filter element into the left carotidartery, bypassing the second occlusive element. In embodiments where theocclusive elements are balloons, the deployment of the occlusiveelements comprises inflating the balloons. In some embodiments, theembolic protection method further comprises delivering a filter devicewith an independent filter element through a lumen of the filtrationcatheter into the left carotid artery and deploying the independentfilter element to filter blood flowing into the left carotid artery. Ingeneral, the flow rate of filtered blood flow into the right carotidartery is at least about 50% of the natural blood flow. The positioningof occlusive element can be assisted with x-ray visualization. In someembodiments, the embolic protection method further comprises applyingaspiration to the integrated filter element through a main lumen of thefiltration catheter to remove the emboli trapped inside the integratedfilter element. The method in general further comprises collapsing theocclusive element followed by removing the filtration catheter from thepatient. The embolic protection method can further comprises performingan endovascular procedure on the heart, delivering a heart valvedelivery catheter through the descending aorta or the subclavian arteryto the heart to effect at least a step related to removal of a heartvalve or the placement of a prosthetic heart valve, or performing asurgical procedure on the heart while the filtration system is filteringflow into the carotid arteries. In one embodiment, the endovascularprocedure comprises replacement of the aortic valve while the filtrationsystem is filtering flow into the carotid arteries.

In a fourth aspect, the invention pertains to a biocompatible filtrationcatheter that can comprise a proximal section; a proximal filter elementintegrated as part of a wall of the catheter at or near the distal endof the proximal section; a bridge section extending in a distaldirection relative to the proximal filter and comprising a proximalconduit, a distal conduit and an inflow opening between the proximalconduit and the distal conduit; a distal filter element integrated aspart of the wall of the catheter at or near the distal end of the distalconduit; a distal section extending in a distal orientation from thedistal filter element; a proximal occlusive element associated with theexterior of the proximal conduit between the proximal filter element andthe inflow opening; and a distal occlusive element associated with theexterior of the distal conduit between the distal filter element and theinflow opening. The inflow opening is between the distal filter elementand the proximal filter element of the catheter. The proximal conduit ofthe catheter provides fluid communication between the proximal filterelement and the inflow opening and the distal conduit of the catheterprovides fluid communication between the distal filter element and theinflow opening. The occlusive elements of the filtration catheter canextend radially outward from the exterior of the conduits around thecircumference of the catheter. The integrated filter elements of thefiltration catheter provide fluid communication between the inflowopening and the exterior of the catheter through the conduits. In someembodiments, the filtration catheter further comprises a distal guideport at or near the distal end of the distal section. In someembodiments, the distal section of the filtration catheter comprises aclosed tubing section. The filtration catheter can have a diameterbetween about 5 Fr to about 7 Fr. The integrated filter elements of thefiltration catheter comprise approximately the same diameter as thecatheter. In some embodiments, the occlusive elements of the filtrationcatheter are compliant balloons. The filtration catheter can comprise atleast one balloon lumen inside the catheter to inflate the balloons. Insome embodiments, the integrated filter elements of the filtrationcatheter comprise interwoven fibers. The interwoven fibers of thefiltration catheter can further comprise metal filaments and or surfacecapillary fibers. In some embodiments, the proximal filter element ofthe filtration catheter has a length from about 10 mm to about 80 mmwhile the distal filter element has a length from about 5 mm to about 30mm. The filter elements of the filtration catheter can have pore sizesof about 50 micron to about 500 micron. The distance between theocclusive elements of the filtration catheter can be about 30 mm toabout 120 mm. In some embodiments, the filtration catheter can furthercomprise sheath slidably positioned over the catheter having aconfiguration extended in a distal direction relative to the cathetercovering occlusive elements in an unextended configuration.

In a fifth aspect, the invention pertains to a biocompatible filtrationcatheter that can comprise a proximal section; a proximal filterelement; a bridge section extending in a distal direction relative tothe proximal section and comprising a proximal conduit, a distal conduitand an inflow opening; a distal filter element; a distal sectionextending in a distal orientation relative to the distal filter elementand comprising a guide port at the distal end; a proximal occlusiveelement associated with the exterior of the proximal conduit; and adistal occlusive element associated with the exterior of the distalconduit. The inflow opening of the filtration catheter is between thedistal filter element and the proximal filter element. The proximalconduit of the filtration catheter provides fluid communication betweenthe proximal filter element and the inflow opening, and the distalconduit of the filtration catheter provides fluid communication betweenthe distal filter element and the inflow opening. The occlusive elementsof the filtration catheter can extend radially outward from the exteriorof the conduit around the circumference of the catheter. The conduits ofthe filtration catheter provide fluid communication between the inflowopening and the exterior of the catheter through the filter elements.

In a sixth aspect, the invention pertains to a method for restrictingemboli from entering the carotid arteries in a patient using afiltration catheter that comprises a proximal section, a distal filterelement, a proximal filter element at or near the distal end of theproximal section, a bridge section connecting the proximal filterelement and the distal filter element and comprising a proximal conduitand a distal conduit, and an inflow opening between the distal filterelement and the proximal filter element. The embolic protection methodcomprises delivering a guidewire from the right subclavian artery,through the brachiocephalic artery, along the aortic arch to the leftcarotid artery; tracking the filtration catheter over the guidewire toposition the distal occlusive element inside the left carotid artery,the proximal occlusive element inside the brachiocephalic artery, andthe inflow opening inside the aortic arch; and expanding the proximalocclusive element and the distal occlusive element to make sealingengagements with the walls of the brachiocephalic artery and the leftcarotid artery respectively to inhibit direct blood flow from enteringinto respective arteries while redirecting the blood flow to enter theinflow opening, to flow through the conduits and then to exit the filterelements to provide filtered blood flow into the left carotid artery andthe right carotid artery from the aorta. The flow rate of filtered bloodflow is at least about 50% of the natural blood flow in respectivearteries. In some embodiments, the flow rate of filtered blood flow isat least about 70% of the natural blood flow in respective arteries. Thepositioning of occlusive elements can be assisted with x-rayvisualization. In some embodiments, the embolic protection methodfurther comprises applying aspiration to the filter elements through amain lumen of the filtration catheter to remove the emboli trappedinside the filter elements. The method further comprises collapsing theocclusive elements followed by removing the filtration catheter from thepatient.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic diagram of a filtration catheter according to oneembodiment of the invention.

FIGS. 1B-1G are sectional views taken at respective different lines offiltration catheter of FIG. 1A.

FIGS. 1H and 1I are fragmentary side views of alternative embodiments ofthe distal section of the filtration catheter of FIG. 1A.

FIG. 2A is a schematic diagram of the filtration catheter of FIG. 1Awith arrows illustrating blood flow through the conduit and theintegrated filter elements.

FIG. 2B is a side view of an obturator that can be used to facilitatedelivery of the filtration catheter of FIG. 1A.

FIG. 2C is a side view of a sheath that can be used to facilitateretrieval of the filtration catheter of FIG. 1A.

FIG. 3A is a schematic diagram illustrating the filtration catheter ofFIG. 1A placed inside an aortic arch by way of the right subclavianartery.

FIGS. 3B and 3C are a set of photographs of a specific embodiment of theintegrated filter elements with emboli trapped inside the fiber braidsof the filter elements.

FIG. 3D is a schematic diagram illustrating a rapid exchange version ofthe filtration catheter of FIG. 1A placed inside an aortic arch by wayof the right subclavian artery.

FIG. 4A is a schematic diagram of a second type of filtration systemaccording to one embodiment of the invention with a filter devicedelivered through the lumen of a second type of filtration catheter.

FIGS. 4B-4D are sectional views taken at respective different lines offiltration system of FIG. 4A.

FIG. 4E is an enlarged fragmentary side view of the independent filterelement of the filtration system of FIG. 4A showing the detailedfeatures of the filter basket.

FIG. 5A is a schematic diagram of the filtration catheter of FIG. 4Aplaced inside a blood vessel with arrows illustrating blood flow throughthe conduit and the integrated filter element.

FIG. 5B is a side view of an obturator that can be used to facilitatedelivery of the filtration catheter of FIG. 4A.

FIG. 5C is a side view of a sheath that can be used to facilitateretrieval of the filtration system of FIG. 4A.

FIG. 5D is a schematic sectional view of an embodiment of a surfacecapillary fiber.

FIGS. 5E and 5F are schematic sectional views of two contrasting roundfibers.

FIG. 5G is a fragmentary side view of an alternative embodiment of afilter device that can be delivered through the filtration catheter ofFIG. 4A.

FIG. 6 is a fragmentary view of a specific design of a filtrationcatheter with two integrated filtration elements.

FIGS. 6A-6E are a set of sectional views taken along respective lines offiltration catheter of FIG. 6.

FIG. 6F is a fragmentary side view of the proximal fittings of thefiltration catheter of FIG. 6.

FIG. 6G is a plan view of the proximal fittings of FIG. 6F looking in aproximal direction along the catheter axis from the fragmentary view ofFIG. 6F.

FIGS. 7A-7L are a set of drawings illustrating steps of a representativeprocess of using a filtration catheter during an endovascular procedure.

FIG. 8A is a schematic diagram illustrating the filtration system ofFIG. 4A placed inside an aortic arch by way of the right subclavianartery.

FIG. 8B is a schematic diagram illustrating a rapid exchange version ofa second type of filtration system placed inside an aortic arch by wayof the right subclavian artery.

FIG. 8C is a schematic diagram illustrating an embodiment of a secondtype of filtration system comprising the filtration catheter of FIG. 4Aand the filter device of FIG. 5G placed inside an aortic arch by way ofthe right subclavian artery with an retrieval catheter.

FIG. 9A is a photograph of an embodiment of the first type of filtrationcatheter placed inside a glass scale model of aortic arch by way of themodel right subclavian artery.

FIG. 9B is a photograph of a section of filter element of the filtrationcatheter of FIG. 9A with emboli trapped inside the interwoven fibers ofthe filter elements of the filtration catheter.

FIG. 10A is a photograph of an embodiment of the second type of thefiltration system placed inside a glass scale model of aortic arch byway of the model right subclavian artery.

FIG. 10B is a photograph of a section of filter element of thefiltration catheter of FIG. 10A with emboli trapped inside theinterwoven fibers of the integrated filter element of the filtrationcatheter.

DETAILED DESCRIPTION

The filtration systems described herein provides protection to the leftcarotid artery and the brachiocephalic artery, which leads to the rightcarotid artery, against embolization from the aortic arch duringprocedures, such as transcatheter aortic-valve implantation (TAVI),aortic heart valve repairs and other procedure on or near the heart.Improved embolic protection devices are described herein with aconvenient construction that has two filters configured for easydelivery and removal while restricting emboli from entering the carotidarteries during heart valve replacement procedures and otherendovascular procedures that have a risk of providing emboli into theaortic arch. Two general system designs are presented, and both systemsare designed to provide filtration of flow from the aorta into both theleft carotid artery and right carotid artery while providing littleobstruction along the aortic arch.

Filtration systems are described that provide for introduction of adistal end of the filtering catheter into the brachiocephalic arterywith a portion of the system configured for extending from thebrachiocephalic artery to the left carotid artery such that followingdeployment, flow from the aorta can be filtered into both carotidarteries. A first filtration system has a catheter that can span fromthe entrance into the brachiocephalic artery along the aortic arch tothe left carotid artery. The catheter of this first type of system hasan inflow opening into the interior lumen to provide internal flow intoboth a distal direction and a proximal direction relative to the inflowopening and respective filters built into the wall of the catheter toprovide filtered flow. With the use of appropriately positioned balloonsor other flow obstructers along the exterior of the catheter, filteredflow can be provided to the left carotid artery and into thebrachiocephalic artery, for flow into the right carotid artery. In thesecond filtration system, a filtration catheter is designed forpositioning the distal section in the brachiocephalic artery, and thefiltration catheter comprises a filter integrated with the catheter wallalong with a balloon or other flow obstruction device on the catheterouter surface to provide filtered flow from a distal opening out throughthe filter at a position proximal to the obstruction device within thebrachiocephalic artery. For the second filtration system, a filterassociated with a guide structure can be extended from the distalopening of the catheter for placement of the filter into the leftcarotid artery. Thus, each of the two filtration systems describedherein comprise a filtration catheter. For consistency and ease of thediscussion, the type of filtration catheter of the first type offiltration system is referred to as the first filtration catheter whilethe type of filtration catheter of the second type of filtration systemis referred to as the second filtration catheter. As is conventional inthe art, in a percutaneous or endovascular procedures, a distaldirection refers to a position further from the insertion point into thebody along the path of the device, and a proximal direction refers to aposition closer to the insertion point.

The embolic protection systems comprise a filtration catheter havingeither one or two occlusive elements to block unfiltered blood flow intoone or both carotid arteries. The first filtration catheter provides aconduit placed inside the aortic arch with filter elements placed alongthe conduit to trap the emboli before the blood exits the conduit andenters the carotid arteries as well as the brachiocephalic artery. Inparticular, the filter elements generally are incorporated into thestructural wall of a filtration catheter to provide filtered flow pastthe respective occlusive elements. In the second system, just one filterelement is provided through incorporation into the structural wall ofthe filtration catheter, and another filter connected to a guidestructure is used to provide filtration for the left carotid arteryfollowing placement from the brachiocephalic artery along the aorticarch. The filtration catheters provide desirable delivery into theappropriate locations in the vessels as well as convenient retrievalafter completion of the procedure with a low risk of releasing emboliinto the carotid arteries during removal of the catheter. Eachfiltration system design provides particular advantages. With the firstfiltration system, because the filter elements are stationary relativeto the other elements of the catheter, the filtration catheter can bequickly removed with little risk of releasing the emboli at the end ofthe procedure. With the second filtration system, the delivery of thefilter into the left carotid artery can be accomplished with only aguide structure extending across the aortic arch.

The filtration systems are designed for delivery through the rightsubclavian artery with a component traversing a portion of the aorticarch from the brachiocephalic artery to reach the left carotid artery.In the first system design, only the body of the filtration catheter,which would occupy a small volume relative to the other endovasculardevices used in the aorta, resides along the aortic arch during theoperational process. For the second system design, only a guidestructure or the like, which would occupy a very small volume, residesalong the aortic arch during the operational process. Both systemsinvolve deployment of a first occlusive element in the brachiocephalicartery. Upon deployment of a second occlusive element in the leftcarotid artery for the first system or the deployment of a filterstructure in the left carotid artery for the second system, thefiltration system provides simultaneous filtration of blood into rightcarotid artery and into the left carotid artery. Thus, the practicalfiltration systems described herein do not significantly interfere withblood flow or other devices in the aortic arch, provides effectiveembolic protections to the carotid arteries, and can be quickly removedwithout significant risk at the end of a procedure. In some embodiments,the catheter may include one or more balloons as occlusive elements tobe used in conjunction with filters that effectively protect the carotidarteries by capturing/deflecting clots from the heart arteries and/orvalves. The balloon in general can be soft and compliant to secure theposition of the catheter and to re-direct blood in the vessel to flowthrough a filter element integrated with a catheter wall. In a specificcommercial design, the filtration catheter may be delivered via a 6-7French (Fr, 1 Fr=(⅓) mm) introducer sheath through a right side upperextremity access.

In general, the filtration catheter of either filtration system can betracked through a brachial or radial approach without kink or damageduring delivery. The filtration catheter for either filtration systemadditionally can be designed to withstand normal torque forces during arelevant medical procedure. The filtration catheter in general can besoft and atraumatic to blood vessels. The concept of delivering filterelements through the right subclavian artery into the right carotidartery or brachiocephalic artery and the left carotid artery so aportion of the delivery or guide structure spans between thebrachiocephalic artery and the left carotid artery inside the aorticarch has been described in published U.S. Pat. No. 8,206,412 to Galdoniket al., entitled “Embolic Protection During Percutaneous Heart ValveReplacement and Similar Procedures,” incorporated herein by reference.The filtration catheters described herein integrate filter element(s)directly on the shaft of a catheter to provide filter element(s) thatdoes not require extending and collapsing procedures, thus significantlysimplify the delivery and retrieval procedures while providing desiredretention and removal of the emboli. Also, the filter designs integratedinto the catheter wall as described herein can provide for desired flowlevels through the filter element(s) with practical filter designswithin the size constraints imposed by the vessels sizes.

With respect to the first type of filtration system design, thefiltration catheter comprises a distal section, a distal filter element,a bridge section with two occlusive elements and an inflow opening, aproximal filter element and a proximal section in which adjacentelements are appropriately attached to form an integrated filtrationcatheter. In some embodiments, the filtration catheter may have a mainlumen that extends through the entire length of the catheter, and themain lumen can be used as a guide lumen if the lumen has a distal guideport. The bridge section of the filtration catheter is designed to havea proximal conduit and a distal conduit that can be part of the mainlumen to provide fluid communication from the inflow opening to theproximal filter element and the distal filter elements respectively. Thefiltration catheter for the second filtration system is an alternativecatheter design comprising a flow control section with a singleocclusive element, a filter element proximal to the occlusive elementand a proximal section.

With respect to the first type of filtration catheter structure, thedistal section of the filtration catheter is attached at or near itsproximal end with the distal filter element. The distal section ingeneral is designed to restrict unfiltered flow from exiting theinterior lumen of the catheter. In general, the filtration catheter canbe designed to ride over a guide structure, such as a guide wire, suchas through the main lumen for delivery of the catheter into a desiredlocation for use. In some embodiments, the distal section can have aguide port at the distal tip. The guide port, if present, should have asmall clearance over a corresponding guide structure such that little ifany unfiltered blood can flow from the guide port, although a separateguide lumen can be used if desired to separate the guide structure fromthe blood flow or alternatively a fixed guide structure can be connectedat the distal end of the distal section. If the filtration catheter isdesigned to ride over a guide structure, the main lumen for the guidestructure can extend from the distal section to the proximal section ofthe catheter, with the distal portion of the main lumen modified torestrict unfiltered blood flow through the distal end of the catheter.In alternative embodiments, a coil or guide wire structure can extendfrom the distal end of the distal section to facilitate delivery of thefiltration catheter.

The second type of filtration catheter design does not have a bridgingsection since the catheter is not intended to bridge the aortic arch,and the flow control section of this catheter can be considered toreplace the bridge section or to involve a truncated portion of thebridge section. The flow control section of the second type offiltration catheter design generally has a distal opening, which canhave a diameter approximately the size of the catheter inner lumen. Forboth type of general filtration catheter designs, appropriate radiopaquemarkers can be incorporated into the filtration catheter to assist inthe placement of the catheter into patient.

The second type of filtration catheter has a single integrated filterthat is positioned for use to filter blood flowing into thebrachiocephalic artery for further flow into the right carotid artery.Also, a single occlusive element is mounted near the distal end of thesecond type of filtration catheter such that the deployed occlusiveelement directs flow into the distal opening and out through theintegrated filter element. An independent filter, generally mounted on aguide structure can be delivered through the lumen of the filtrationcatheter and out through the distal opening, bypassing the occlusiveelement. The independent filter can be directed along the aortic archfor placement within the left carotid artery to filter flow from theaorta into the left carotid artery.

An integrated filter element in the filtration catheters is generallydesigned as a porous tubular section that essentially replaces a segmentof the catheter with a filtering porous structure. The length of thefilter element along the longitudinal axis of the filtration cathetercan be selected to provide the desired degree of flow and filtrationcapacity. For embodiments with two tubular filtration elements, e.g., afirst type of filtration catheter, the tubular filter elements may ormay not have the same dimensions as each other. While the tubular filterelement can generally be formed from any porous material, such as amembrane with appropriately selected holes drilled through the material.In some embodiments, the filter element can be formed from woven bundlesof fibers with or without additional components. In general, the fiberscan be polymer fibers, metal wires or combinations thereof. Inparticular, bundles of polymer surface capillary fibers have been foundto provide desired filtration properties while helping to maintaindesired flow through the filter structure. In some embodiments, thefiber bundles with surface capillary fibers can further comprisedifferent polymer fibers and/or metal wires, such as Nitinol wires, toprovide additional structural stability to the filter elements. Theweave of the filter elements can be formed to provide desired degree offiltration with respect to capture of emboli with desired size rangeswhile in some embodiments maintaining at least 50% of normal blood flow.

Filtration catheters with filter elements placed within the catheterlumen to provide filtered flow through a port in the catheter wall aredescribed in U.S. Pat. No. 8,206,412 to Galdonik et al., entitled“Embolic Protection During Percutaneous Heart Valve Replacement andSimilar Procedures,” incorporated herein by reference. In contrast, theintegrated filters of the improved filtration catheters described hereinprovide for improved flow of filtered blood without obstructing theinner lumen to allow for the passage of an independent filter, suctioncatheters, sheaths or the like to facilitate the procedure. Inparticular, the second type of filtration system described hereinadvantageously uses the open lumen within the filtration catheter forthe delivery of the second independent filter for placement in the leftcarotid artery. For the sake of clarity, a reference to a carotid arteryherein can be to the common carotid artery and/or to the interiorcarotid artery that supplies blood to the brain.

With respect to the first type of filtration catheter, the bridgesection of the filtration catheter is generally designed for placementspanning a segment along the aortic arch. Within the catheter structure,the bridge section is connected between the distal filter element andthe proximal filter element. The bridge section comprises an inflowopening to provide for flow of blood from the aortic arch to the filterelements within a conduit or lumen extending through the bridge section.The size of the inflow opening can balance the mechanical strength andflexibility of the bridge section while providing good flow through thefilter elements to the carotid arteries. The bridge section furthercomprises a proximal conduit and a distal conduit relative to the inflowopening that respectively provide flow to the interior of the proximalfilter and the distal filter. Thus, the inflow opening provides flowaccess through the bridge section to the interior of the proximal filterelement and the distal filter element, and the inflow opening cancomprise a plurality of distinct openings to provide this inflowfunction. Similarly, if the bridge section has sufficient mechanicalstrength, a significant portion of the catheter wall can be opened asinflow opening to provide the flow into the proximal conduit and thedistal conduit.

The bridge section of the first type of filtration catheter alsocomprises a proximal occlusive element and a distal occlusive element.The proximal occlusive element is associated with exterior of filtrationcatheter along the proximal conduit, and the distal occlusive element isassociated with exterior of filtration catheter along the distalconduit. While one or both occlusive elements can comprise a mechanicaloccluder or the like, balloons as convenient occlusive elements can beeffectively expanded and deflated at appropriate times in the procedure.One or two balloon lumens can be used to supply fluid to inflate theballoons from the proximal portion of the filtration catheter exteriorto the patient. If a single balloon lumen is used, the balloons areinflated and deflated roughly simultaneously although the flow can bedesigned for the balloons to roughly inflate in series, while twoballoon lumens provide for independent control of inflation anddeflation of the balloons. The balloons may not have the same sizes aseach other since the balloon configured for deployment in thebrachiocephalic artery may have a larger size than the balloonconfigured for deployment in the left carotid artery. The flow controlsection of the second type of filtration catheter has a single occlusiveelement corresponding to the proximal occlusive element of the bridgesection of the first type of filtration catheter and can be formed withthe similar structures described above in this paragraph withappropriate simplifications associated with having only a singleocclusive element.

With respect to the first type of filtration catheter, conduits of thebridge section extend inside the filtration catheter and past theocclusive elements relative to the inflow opening and connect to therespective tubular filter elements such that flow redirected by theocclusive elements flows into the inflow opening, past the occlusiveelements through the internal conduit, and exits through the filterelements to reenter into the blood vessels. The flow control section ofthe second type of filtration catheter similarly has a conduit extendingpast the occlusive element such that flow redirected by the occlusiveelement flows into the distal opening of the catheter, past theocclusive element through the conduit, and exits through the integratedfilter element to reenter into the blood vessel.

In some embodiments, the catheter body can be formed from polymer and beintegrated with the filter element(s), for example, using an adhesivebond, a mechanical fastener, heat bonding, polymer reflow to embed theedge of the filter element, or a combination thereof. In general, thefiltration catheters and the joints of the catheter are sufficientlystrong to withstand normal tensile loads during the procedure.

The proximal section of either type of filtration catheters is connectedto the proximal filter element to form an integrated structure. Theproximal section is generally relatively long with a proximal end of theproximal section designed to extend from the patient during theprocedure, and the proximal end has appropriate fittings, as describedfurther below, to provide for performing the procedure. In someembodiments, the filtration catheter is designed for over-the-wiredelivery in which the proximal section comprises a tubular shaftextending from the proximal filter with a length suitable to extend fromthe patient after delivery. As noted above, for embodiments with balloonocclusive elements, one or two balloon lumen can extend from theballoons through the proximal section to appropriate fittings at or nearthe proximal end of the proximal section. A main lumen or a guide lumencan provide for a guide structure extending approximately the length ofthe device. In alternative embodiments, the filtration catheter can beconfigured for a rapid exchange of a guide structure through a guideport on the filtration catheter so that the guide structure does notextend through the most or all of the length of the proximal section. Insome embodiments, a loading tool can be used for loading the guidestructure through the guide port, for example, as described in U.S. Pat.No. 8,021,351 to Boldenow et al., entitled “Tracking AspirationCatheter,” incorporated herein by reference. In some embodiments for thefirst type of filtration catheter, a guidewire lumen can extend alongthe catheter shaft from a distal guide port at or close to the distalend of the distal occlusive element to a rapid exchange guide portproximal to the proximal filter element. The proximal end of theproximal section can comprise appropriate handles or fittings, such asLuer fittings, hemostatic valves and the like, to account for the exitof a guide structure, connection to devices, such as syringes, toprovide for inflation or deflation of balloon, or other connections, asdesired.

In use, either type of the filtration catheters can be delivered into anartery in the patient's right arm, for example, using conventionalendovascular procedures, introducer, hemostatic fittings and the like.The filtration catheter is guided with the distal end of the catheterinto the brachiocephalic artery. In general, the first type offiltration catheter is long enough to reach left carotid artery from theinsertion point in the patient's right arm. For the first type offiltration catheter, a separate guide structure or a distal coil or wiretip can be guided along the portion of the aortic arch between thebrachiocephalic artery and the left carotid artery to enter the leftcarotid artery. If a separate guide structure is used, the first type offiltration catheter can then be tracked over the guide structure toplace the distal occlusive element within the left carotid artery. Withproper placement of the first type of filtration catheter, the distalocclusive element is within the left carotid artery, the proximalocclusive element is within the brachiocephalic artery and the inflowopening is inside the aortic arch. With proper placement of the secondtype of filtration catheter, the occlusive element is within thebrachiocephalic artery, with the distal opening close to the entrance ofartery to aortic arch. The occlusive element(s) can be deployed with theplacement of the device verified, generally with x-ray techniques. Soft,compliant balloon(s) can be used as occlusive element(s) to secure theposition of the catheter as well as to re-direct flow in the vesselthrough the filter element(s). For the first type of filtrationcatheter, the occlusive elements can be deployed simultaneously orsequentially.

Once properly placed, the second type of filtration catheter can be usedto deliver another embolic protection filter device such as commerciallyavailable FIBERNET®, SPIDER®, or FILTERWIRE® to the left carotid artery.In particular, the independent filter is generally tracked out from thedistal opening of the second type of filtration catheter on or over aguide structure. The guide structure is guided to the left carotidartery so that the independent filter can be deployed to filter flowinto the left carotid artery. In particular, a FIBERNET® filter has aconvenient low profile and delivery on an associated guide structure.

With the selected filtration system deployed, a procedure, such as aheart valve replacement, can be performed on the heart that creates arisk of emboli generation in the aortic arch. Deployment of the firsttype of filtration catheter generally comprises extension of the twoocclusive elements respectively in the left carotid artery and thebrachiocephalic artery to redirect flow into the two integrated filters.Deployment of the second type of filter element comprises extension ofthe independent filter element in the left carotid artery and theextension of the single occlusive element in the brachiocephalic arteryto deflect flow through the integrated filter element to provide forfiltered flow into the brachiocephalic artery. After completing theprocedure and the risk of emboli generation has decreased to appropriatelevels, the occlusive element(s) can be collapsed to an appropriateconfiguration, and the filtration catheter can be removed from thepatient along with an independent filter element if applicable. In someembodiments, aspiration maybe used to remove the emboli trapped insidethe filter element(s) at the time of and/or prior to the recovery of thefiltration catheter from the patient.

In some embodiments, it may be desirable to use an obturator tofacilitate the delivery of the filtration catheter. The obturator can beextended through the main lumen and through the conduits of the bridgesections to provide internal mechanical support to the filter element(s)as well as to the inflow opening of the bridge section in the case ofthe first type of filtration catheter. Alternatively, an external sheathmay be used to cover the filter element(s) including the bridge sectionin the case of the first type of filtration catheter during deliveryand/or retrieval processes. In embodiments when suction is used for thefirst type of filter element, a sheath may be used to cover the inflowopening to help transmit the suction out through the distal filterelement.

In general, the filtration catheter disclosed herein provides effectivefiltration with insured apposition of the catheter during the procedure.The filtration catheter provides little interference in the aorta andadditionally accommodates various aortic arch anatomies. Simpleoperation procedure is required to operate the filtration catheter withessentially no recovery step involved in some embodiments.

Filtration Systems and Catheter Structure

A first type of filtration system is designed such that a singlefiltration catheter structure can be used to deliver two filters from abrachiocephalic approach with a bridge section of the catheter spanningthe aortic arch. The first type of filtration system comprises a firsttype of filtration catheter as its core component that is used alongwith suitable fittings, any selected optional delivery components and/orrecovery components, components to provide for deployment of occlusiveelements and the like. Occlusive elements of the first type offiltration catheter are positioned to block the flow of unfiltered bloodfrom the aortic arch into the left carotid artery as well as into thebrachiocephalic artery from which emboli could flow into the rightcarotid artery. As noted above, an opening into the catheter at thebridge section of the first type of filtration catheter provides forflow into the interior of the catheter for flow from the aorta in both adistal direction and proximal direction relative to the opening.Filtered flow can exit the catheter past the respective occlusiveelements through a proximal filter and a distal filter, both of whichare formed as a portion of the catheter wall. Desirable flowcharacteristics can be obtained for filtered flow beyond the occlusiveelements in the first type of filtration catheter.

A second type of filtration system is designed such that a catheterstructure can be used to deliver an filter element that is integrated onthe catheter into a brachiocephalic artery while a guide structure of anindependent filter device is deployed extending from a distal opening ofthe catheter structure and spanning the aortic arch to the left carotidartery. In the case of the second type of filtration catheter, anocclusive element is positioned to block the flow of unfiltered bloodfrom the aortic arch into the brachiocephalic artery from which embolicould flow into the right carotid artery. The distal opening offiltration catheter allows blood from the aorta flow into the interiorof the catheter. Filtered flow can exit the catheter past the occlusiveelement through the integrated filter element that is formed as aportion of the catheter wall, while the independent filter element ofthe filtration system from the filter device filters the blood flowsinto the left carotid artery. Desirable flow characteristics can beobtained for filtered flow in both right and left carotid arteries ofthe second type of filtration system. The second type of filtrationsystem may also comprise fittings, optional delivery components and/orrecovery components, components to facilitate deployment of theocclusive element and other desired components suitable to facilitatethe procedure.

First Type of Filtration Catheter

Referring to FIGS. 1A-1I, a filtration catheter 100 is illustrated toexemplify the features of the first type of filtration catheter. FIG. 1Ais a fragmentary side view of the filtration catheter 100 with aproximal portion 136 and proximal end 134. Enlarged cross sectionalviews along the B-B, C-C, D-D, E-E, F-F, and G-G lines of filtrationcatheter 100 are illustrated in FIGS. 1B-1G respectively. As shown inFIG. 1A, filtration catheter 100 comprises a distal section 110 d, adistal integrated filter element 102, a proximal section 110 p, aproximal integrated filter element 108, a bridge section 110 b betweenthe two filter elements that comprises an inflow opening 112 on theshaft, a conduit 114 that comprises a proximal conduit 114 a thatprovides fluid communication between the proximal filter element 108 andthe inflow opening 112 and a distal conduit 114 b that provides fluidcommunication between the distal filter element 102 and the inflowopening 112.

Both distal filter element 102 and proximal filer element 108 areintegrated structures that substitute for a section of the wall of thefiltration catheter, which can have similar diameters to the rest of thecatheter. In alternative embodiments, the filter elements can have aslightly different diameter from the remaining portions of the catheter,such as a slightly larger diameter generally without complicating thedelivery of the filtration catheter. Also, particular segments ofconduits or shaft of the device may or may not have the same diameter asother segments. The filtration catheter has a main lumen 130 thatextends from proximal section 110 p through the length of the cathetersuch that the internal lumen of the tubular filter elements, theconduits can all be considered the part of the main lumen. Filtrationcatheter 100 additionally comprises a proximal balloon 116 and a distalballoon 118 that can extend from the exterior of the shaft. Proximalballoon 116 is positioned between inflow opening 112 and proximal filterelement 108 and distal balloon 118 are positioned between inflow opening112 and distal filter element 102. Other occlusive elements, such as asupported occlusive membrane can be used instead of balloon(s). Theballoons and/or the supported membranes used can have appropriate shape,diameter, and composition. Occlusive balloons have been described, forexample, in published U.S. patent application 2011/0093000 to Ogle etal., entitled “Vascular Medical Devices With Sealing Elements andProcedures for the Treatment of Isolated Vessel Sections,” incorporatedherein by reference. In FIG. 1A proximal balloon 116 is shown to havelarger diameter than distal balloon 118, which can be appropriate forthe respective vessel sizes.

In general, the filter elements can independently have a desiredstructure with respect to integration of the filter elements into thewall of the catheter. For example, the filters can be formed from atubular segment with holes drilled through the wall of the tubularsegment with diameters selected to block emboli with larger sizes.However, in embodiments of particular interest, the filters are formedfrom fibers that are formed into tubular sections that replace a sectionof the catheter wall. As will be discussed further below, the fibersused in the filter elements can be polymer fibers, metal fibers such asNitinol, or a combination thereof. In some embodiments, filter elementswith at least some of the fibers being polymer surface capillary fibersmaybe constructed and used. In general, the thickness and shape of thefibers, the tightness or density of the braid or wave of the fibers, thepique per inch of the braid or wave, and the length of the filterelements can all be designed to suit selected filtration performancewhile balancing the flow through the filters. The length of the proximalfilter element and the length of the distal filter element can be thesame or different from each other. In the embodiment shown in FIG. 1A,the proximal filter element 108 is longer than distal filter element102, which can provide greater flow rates into the largerbrachiocephalic artery. The diameter of catheter 100 in general can bedesigned to be suitable for placement inside aortic arch percutaneously.Filter structure 100 may employ radio opaque bands or markers at variouslocation of the catheter body to facilitate visualization during thedelivery and placement of the device.

Distal section 110 d of the filtration catheter can be designed torestrict or prevent flow of unfiltered blood out from the catheter, anddistal section 110 d can be designed to facilitate placement of thecatheter with the distal section within the left carotid artery. Asshown in FIG. 1A, distal section 110 d comprises a tapered tip, andfiltration catheter 100 can be delivered on a guide wire 120 thatextends from a distal guide port 122 at or near the distal end of distalsection 110 d. In an alternative embodiment shown in FIG. 1H, distalsection 121 has an integral wire 123 extending in a distal directionfrom a closed distal tip. The length of integral wire 123 can beselected to provide for guiding the distal tip along the aortic archinto the left carotid artery and can be, for example, from about 1 cm toabout 15 cm, in further embodiments from about 1.5 cm to about 12 cm andin other embodiments from about 2 cm to about 10 cm. A person ofordinary skill in the art will recognize that additional ranges oflengths within the explicit ranges above are contemplates and are withinthe present disclosure.

In another alternative embodiment shown in FIG. 1I, distal section 131comprises a separate guide lumen 133 with main lumen 137 within distalsection 131 closed to prevent flow of unfiltered blood from distalsection 131. Guide lumen 133 is shown with guidewire 135 extending fromthe distal end of guide lumen 133. Guide lumen 133 can extend along mostor all of the length of filter catheter 100 for an over the wire design,or guide lumen 133 can terminate at a location within the patient'svasculature during use for a rapid exchange configuration. In general,with a rapid exchange configuration, guide lumen 133 generally extendsin a proximal direction at least past proximal occlusive element. SeeFIG. 3D below for further discussion of a rapid exchange configuration.With a separate guide lumen, the catheter does not necessarily have amain lumen extending to the proximal end of the catheter.

Cross sectional views along the lines C-C to G-G of the device revealsinternal structure of the catheter at various positions along itslength. As noted above, in general any reasonable structure can be usedfor each of the occlusive elements independently selected, such asmechanical occlusive elements, but the discussion herein focuses onballoon based occlusive elements in both positions, which provideconvenient functionality for the delivery, deployment and recovery ofthe catheter. As shown in FIG. 1B, the proximal section 110 p of thedevice can comprises a balloon lumen 124, a balloon lumen 126, andguidewire 120 within main lumen 130. Although the view in FIG. 1Bindicates the presence of two balloon lumens that are in fluidcommunication with the distal and the proximal balloons, the device canalso be constructed to have only one balloon lumen in fluidcommunication with both the distal and the proximal balloons to inflatethe balloons. The view in FIG. 1C shows that balloon lumens 124 and 126and guidewire 120 extend past proximal filter element 108 with fibers132 surrounding the balloon lumens and the guidewire. The view in FIG.1D indicates that proximal balloon 116 surrounds bridge section 110 b ofthe catheter and the interior of proximal balloon 116 is in fluidcommunication with balloon lumen 124 with guidewire 120 extendingthrough proximal conduit 114 a. The view in FIG. 1E shows inflow opening112 on bridge section 110 b with only one balloon lumen 126 extendingthrough this part of the catheter and with guidewire 120 extendingthrough conduit 114. The view in FIG. 1F shows that distal balloon 118surrounds bridge section 110 b, and the interior of distal balloon 118is in fluid communication with balloon lumen 126 with guidewire 120extending through distal conduit 114 b. The view in FIG. 1G shows thatguidewire 120 extend past distal filter element 102 with fibers 103surrounding the guidewire.

As shown in FIG. 1A, in general for over-the-wire embodiments, theproximal end 134 of a proximal section 110 p of filtration catheter 100comprises a proximal port 140 that provides exit of guidewire 120 fromthe main lumen and other proximal ports such as 138 and 142 that provideinflation or deflation of balloons. Proximal port 140 or other optionalports can provide connection to an aspiration device, such as a syringeor the like, to provide aspiration of the filter elements through themain lumen if desired. Proximal ports 138, 140, 142 can comprise Luerfittings, hemostatic valves or the like.

With respect to the size of the filtration catheter, a larger diameterof the catheter provides a corresponding increase in the ability toallow blood flow into the carotid arteries. The body of the catheter ingeneral can be formed from one or more biocompatible materials,including, for example, metals, such as stainless steel or alloys, e.g.,Nitinol, or biocompatible polymers such as polyether-amide blockco-polymer (PEBAX®), nylon (polyamides), polyolefins,polytetrafluoroethylene, polyesters, polyurethanes, polycarbonates othersuitable biocompatible polymers, copolymers thereof or combinationsthereof. Radio-opacity can be achieved with the addition of markers,such as platinum-iridium or platinum-tungsten or throughradio-pacifiers, such as barium sulfate, bismuth trioxide, bismuthsubcarbonate, powdered tungsten, powdered tantalum or the like, added tothe polymer resin. The shaft in general comprises different sections orportions along the length of the device. The different sections orportions of the shaft can be constructed with the same or differentmaterials. In addition, selected sections or portions of the shaft canbe formed with materials to introduce desired stiffness/flexibility forthe particular section or portion of the catheter. For example,materials with metal wires embedded inside polymer maybe used forpolymeric sections of the shaft or in selected sections of the shaft.Upon heating over the softening temperature of the polymer andsubsequent cooling, the wire can become embedded within the polymer.Suitable wire includes, for example, stainless steel wire, Nitinol wiresor alike, and the wire can be flat or rounded with an appropriate smalldiameter or thickness. The metal wire can add additional mechanicalstrength while maintaining appropriate amounts of flexibility for theshaft of the catheter.

In some embodiments, the overall length of the filtration catheter maybe approximately 80 cm to 160 cm, in other embodiments, the overalllength may be approximately 90 cm to 150 cm, and in additionalembodiments, the overall length may be approximately 100 cm to 140 cm.In some embodiment, the filtration catheter can be fit through anintroducer sheath, including commercially available sheaths. As aspecific example, if a 7 F introducer sheath is used, the outer diameterof the delivered portion of the filtration catheter can have an outerdiameter of no more than approximately 0.077 inches. In general, theouter diameter of the filtration catheter may be about 5 Fr (1.67 mm,0.066 inches) to about 7 Fr (2.3 mm, 0.092 inches), in otherembodiments, about 5.5 Fr to about 6.5 Fr, in additional embodiments,from about 5.75 Fr to about 6.25 Fr. A person of ordinary skill in theart will recognize that additional ranges of the filtration catheterlength and diameter within the explicit ranges above are contemplatedand are within the present disclosure.

The distance between the proximal occlusive element and the distalocclusive element in general need to be long enough for positioning ofthe proximal occlusive element in the brachiocephalic artery and thedistal occlusive element in the carotid artery with a section of thebridging section spanning the aortic arch between the brachiocephalicartery and the left carotid artery. For example, if occlusive balloonsare used, the center to center distance between the two balloons orother occlusive elements can be made from about 30 mm to about 120 mm,in other embodiments from about 35 mm to about 110 mm, in furtherembodiments from about 40 mm to about 100 mm or in some embodiments fromabout 50 mm to about 90 mm. A person of ordinary skill in the art willrecognize that additional ranges of center to center distances withinthe explicit ranges above are contemplated and are within the presentdisclosure. Bridge section 110 b comprises inflow opening 112 which canbe formed through removal of a section of the wall of a tubular element,although the inflow opening can be formed through other structures, suchas the physical connection of a proximal tubular element and a distaltubular element with an appropriate connection that provide for flowinto the respective tubular elements from the inflow opening at theconnection of the elements. Similarly, inflow opening 112 in someembodiments can be essentially an inflow opening in a distal directionand an effectively distinct inflow opening in a proximal direction torespectively provide flow into a distal conduit and a proximal conduitrespectively.

FIG. 2A is a fragmentary side view illustrating the proposed blood flowin the filtration catheter 100 when balloons 116, 118 are deployed,i.e., expanded, in positions along the aortic arch. In use, bloodpotentially with emboli 154 is redirected to enter the inflow opening112, go through the conduit 114 including 114 a, and 114 b of the shaft110 and exit the filtration catheter through the proximal and distalfilter elements 108 and 102 respectively as filtered blood 156 a and 156b respectively. The arrows in the figure are used to indicate thedirection of the blood flow. Also, ancillary components that can be usedin conjunction with the filtration catheter are shown. In particular, anobturator 146 as shown in FIG. 2B can be used to facilitate delivery ofthe filtration catheter, and a sheath 150 with a distal opening 152 asshown in FIG. 2C can be used to facilitate delivery and/or retrieval ofthe filtration catheter. Obturator 146 can be placed into main lumen 130to extend through the conduit 114 including the proximal conduit 114 aand distal conduit 114 b of filtration catheter 100 during delivery overa guidewire 120 through a guide port 148 to protect filter elements 108,102 from damage during delivery. Obturator 146 can have a guide lumen.Sheath 150 can be positioned over the exterior of filtration catheter100 to cover at least a portion of the filtration catheter duringdelivery and/or recovery of the filtration catheter from the patient toprotect the filter elements during delivery and/or to further reduce thechance of any emboli escaping from the filter elements during removal.Also, sheath 150 can be used optionally to cover one or both filtersand/or the inflow opening in the bridge to facilitate application ofsuction within the lumen of the filter structure by restricting flowinto the main lumen from the inflow opening. Thus, during recovery,sheath optionally can be advanced at least past filter element 102, insome embodiments past the inflow opening 112 and in additionalembodiment to cover filter element 108.

FIG. 3A is a schematic diagram illustrating filtration catheter 100 ofFIG. 1A placed inside the aortic arch 160 by way of right subclavianartery 162, with proximal portion 136 placed outside the patient. Insome embodiment, a guidewire 120 extends through right subclavian artery162 to aortic arch 160 through brachiocephalic artery 164. Guidewire 120is extends along aortic arch 160 with a distal portion in left carotidartery 166. With guidewire 120 properly placed inside left carotidartery 166, filtration catheter 100 can then be properly positioned withmain catheter lumen 130 over guidewire 120 for use to filter blood flowfrom the aorta. As shown in FIG. 3A, when properly placed, inflowopening 112 of filtration catheter 100 is located inside aortic arch 160with bridge section spanning between left carotid artery 166 andbrachiocephalic artery 164. Distal balloon 118 and distal filter element102 are placed inside left carotid artery 166 with distal filter element102 positioned distally beyond distal balloon 118. Proximal balloon 116and proximal filter element 108 are placed inside larger brachiocephalicartery 164 with proximal filter element 108 positioned proximallyrelative to proximal balloon 116.

In the position shown in FIG. 3A, the distal balloon and proximalballoon can be deployed to block unfiltered flow into the carotidarteries. With blood flow redirected by extended balloons, blood fromthe aorta along the flow indicated with flow arrows 168 enters inflowopening 112 on the shaft of filtration catheter 100, flows throughconduit 114 including 114 a and 114 b and exit the filtration catheterlumen as filtered blood through the distal filter element and proximalfilter element to enter into left carotid artery 166 and right carotidartery 170, respectively. The flow of the blood is indicated by flowarrows. As shown in FIG. 3A, deployed filtration catheter 100 occupies asmall portion of the space inside the aortic arch 160, leaving the restof the space for procedures, such as heart valve replacement or otherprocedures, e.g., endovascular procedures, on or in the vicinity of theheart. Because filter elements 102, 108 of the filtration catheter arean integral part of the filtration catheter, no distinct deployment orcollapse of the filter elements associated with other filter designs isinvolved. After the completion of the operation, the filtration cathetercan be simply removed with the emboli trapped inside the conduit orwithin the braids or waves of the fibers.

As discussed above, the integrated filter element(s) of the filtrationcatheter can be made of braided fibers at a constant pique. Referring toFIGS. 3B and 3C, photos of a specific embodiment of filter elements 102and 108 are shown made with fiber braids 104 and 132 forming respectivefilter element. Emboli 172, 174 are shown to be trapped inside the fiberbraids 104 and 132 respectively. The enlarged fiber braids also revealmetal wires or filaments 176 and 178 integrated into the fiber braids ofthe filter elements of the filtration catheter.

FIG. 3D shows an alternative rapid exchange embodiment of a filtrationcatheter 200 placed inside the aortic arch 260 by way of the rightsubclavian artery 262, with a proximal portion 236 positioned outsidethe patient. Filtration catheter 200 comprises a main or central lumen230 and a rapid exchange guide wire port 250. Proximal portion 236 mayor may not comprise a main lumen if it is desirable to have access tothe flow, such as for the delivery of a drug.

Guide wire 220 of the this embodiment can be similarly delivered andpositioned inside the aortic arch 260 into the left carotid artery 266through the brachiocephalic artery 264. With the guidewire 220successfully delivered and properly placed inside the left carotidartery 266, the filtration catheter 200 can then be delivered over theguidewire 220 that extends through the rapid exchange port 250, with theguide wire 220 exits at the rapid exchange port 250. FIG. 3D shows theinflow opening 212 of the filtration catheter 200 is located inside theaortic arch 260 with the bridge section of the filtration catheter 200spanning between the left carotid artery 266 and the brachiocephalicartery 264. In general, the rapid exchange catheter embodiments can bedesigned with the guidewire extending through a main catheter lumen 230or a distinct guidewire lumen. While shown in FIG. 3D with rapidexchange port 250 positioned in a proximal position relative to proximalfilter 208, rapid exchange port 250 can be positioned at any pointproximal to proximal occlusive element 216. The distal balloon 218 andthe distal filter element 202 are placed inside the left carotid artery266 with the distal filter element 202 positioned distally beyond thedistal balloon 218. The proximal balloon 216 and the proximal filterelement 208 are placed inside the larger brachiocephalic artery 264 withthe proximal filter element 208 positioned proximally beyond theproximal balloon 216. Arrows 268 are used to indicate blood flow in theaorta enters the inflow opening 212 of the filtration catheter 200,travel through the conduit 214 including 214 a, and 214 b and exit asfiltered blood through the distal filter element and proximal filterelement to enter into the left carotid artery 266 and the right carotidartery 270, respectively.

Second Type of Filtration System

Referring to FIG. 4A, a filtration system 300 is illustrated toexemplify the features of the second type of filtration system. FIG. 4Ais a fragmentary side view of the filtration catheter 304 with aproximal portion 336 and a filter device 350 integrated with thefiltration catheter 304 to represent an embodiment of the second type offiltration system 300. Enlarged cross sectional views along the B-B,C-C, and D-D lines of the filtration system 300 are illustrated in FIGS.4B-4D respectively. The filtration catheter 304 can be used with otherembolic protection filter device, such as commercially availableFIBERNET®, SPIDER™, and FILTERWIRE™. The filter device in generalcomprises a filter element that is supported on a guide structure.Because this filter element is independent from the filtration catheter,it is generally referred to as the independent filter element todifferentiate from the integrated filter elements of the filtrationcatheters discussed herein. As shown in FIG. 4A, filter device 350extends through the lumen 330 of filtration catheter 304. As illustratedin this embodiment, filter device 350 comprises a basket type filterelement 352 associated with the guide structure 320. An enlarged view ofbasket type filter element 352 is shown in FIG. 4E. Features of thefilter element 352 can be seen in this detailed view. Specifically, theindependent filter element 352 comprises a filter basket 354 that isintegrated with an optional strut 356 that is associated with the guidestructure 320. When pushed by a retrieval catheter, strut 356 canfacilitate collapse of filter basket 354 into a low profile retrievalconfiguration. Filter device 350 may optionally comprise a distal tip358 that extends distally beyond the filter basket, which may or may notbe an extension of guide structure 320.

Referring to FIG. 4A, the filtration catheter 304 comprises a shaft 306,an integrated filter element 308, a distal section 310 d extending in adistal orientation from the integrated filter element 308, a balloon 316associated with the exterior of the distal section at or near the distalend of the catheter, a distal opening 312, and a conduit 314, which is alumen within distal section 310 d, that provides fluid communicationbetween the integrated filter element 308 and the distal opening 312. Aproximal portion 336 is connected at or near the proximal end of shaft306. The integrated filter element 308 allows fluid to flow through thewall of the catheter and being filtered. The length of filtrationcatheter can be from about 60 cm to about 180 cm, in further embodimentsfrom about 70 cm to about 160 cm and in other embodiments from about 80cm to about 150 cm. A person of ordinary skill in the art will recognizethat additional ranges within the explicit ranges are contemplated andare within the present disclosure. The integrated filer element 308 is afully integrated structure that is a part of filtration catheter 304,which can have similar diameters to the rest of the catheter, or moreparticularly to adjacent sections of the catheter at the distal side andthe proximal side of the integrated filter element. In alternativeembodiments, the filter element can have a slightly different outerdiameter from the adjacent portions of the catheter, such as a slightlylarger outer diameter generally without complicating the delivery of thefiltration catheter. Also, particular segments of the catheter may ormay not have the same diameter or material as other segments. Forexample, the distal section 310 d of the catheter may comprise a distaltip 322 that is made of different material from the rest of the cathetershaft, and distal section 310 d can have a different outer diameterrelative to shaft 306. In general, the inner diameter of an integratedfilter structure is roughly equal to or greater than the inner diametersof the adjacent sections of catheter, although the inner diameter of theintegrated filter may be smaller than the inner diameter of adjacentsections if this structure does not interfere with other structures orfunctions. In embodiments with a rapid exchange configuration, the rapidexchange port for passage of a guide structure associated with theindependent filter element can be placed between the integrated filterand the occlusive device so that the guide structure does not passthrough the lumen of the integrated filter.

In over-the-wire embodiments, the filtration catheter 304 can have amain lumen 330 that extends through the length of the catheter such thatthe internal lumen 318 of the integrated filter element and the conduit314 can all be considered part of the main lumen. The balloon 316 ispositioned between the distal opening 312 and the integrated filterelement 308. Other occlusive elements, such as a supported occlusivemembrane can be used instead of balloon(s). The balloons and/or thesupported membranes used can have appropriate shape, diameter, andcomposition. Occlusive balloons have been described, for example, inpublished U.S. patent application 2011/0093000 to Ogle et al., entitled“Vascular Medical Devices with Sealing Elements and Procedures for theTreatment of Isolated Vessel Sections,” incorporated herein byreference. In FIG. 4A the balloon 316 is shown in an extendedconfiguration, the extended diameter of the balloon is appropriate forocclusion of specific vessel size. For rapid exchange embodiments, thefiltration catheter may or may not have a main lumen. For appropriateembodiments, a balloon lumen extends from proximal end 334 to balloon316.

In general, the integrated filter element can have a desired structurewith respect to integration of the filter element into the wall of thecatheter. For example, the filter element can be formed from a sheetwith holes drilled through the sheet with diameters selected to blockemboli with larger sizes. However, in embodiments of particularinterest, the filter element is formed from fibers that are braided,woven or otherwise formed into tubular section that can be used toreplace a section of the catheter wall. The fibers used in the filterelement can be polymer fibers, metal fibers such as Nitinol, or acombination thereof. In some embodiments, filter element with at leastsome of the fibers being polymer surface capillary fibers maybeconstructed and used. In general, the thickness and shape of the fibers,the tightness or density of the braid or wave of the fibers, the piqueper inch of the braid or wave, and the length of the filter element canall be designed to suit selected filtration performance while balancingthe flow through the filters. Longer filter elements in general canprovide greater flow rate compared to filter element that is relativelyshorter. The filtration catheter 304 may employ radio opaque bands ormarkers at various locations of the catheter body to facilitatevisualization during the delivery and placement of the catheter.

Cross sectional views along the lines B-B to D-D of the filtrationsystem 300 reveals internal structure of the catheter shaft at variouspositions along its length for this embodiment. As noted above, ingeneral any reasonable structure can be used for the occlusive element,such as mechanical occlusive element, but the discussion herein focuseson balloon based occlusive element, which provides convenientfunctionality for the delivery, deployment and recovery of the catheter.As shown in FIG. 4B, the shaft of the catheter can comprise a balloonlumen 324, and a guide structure 320 within a main lumen 330. The viewin FIG. 4C shows the internal lumen 318 of the integrated filter elementwith the balloon lumen 324 and the guide structure 320 extending pastthe filter element 308 with fibers 332 surrounding the balloon lumen 324and the guide structure 320. The view in FIG. 4D indicates that theballoon 316 surrounds the conduit 314 of the filtration catheter and theinterior of the balloon 316 is in fluid communication with the balloonlumen 324. The guide structure 320 is shown to extend through theconduit 314 of the catheter in FIG. 4D.

The proximal portion 336 of the filtration catheter 304 is shown tocomprise a proximal port 340 that provides exit for guide structure 320from the main lumen, a proximal port such as 338 that provides inflationor deflation of balloon 316, and an optional additional proximal port342 that can an provide connection to an aspiration device, such as asyringe or the like, to provide aspiration of the filter element throughthe main lumen if desired. Proximal ports 338, 340, 342 can compriseLuer fittings, hemostatic valves and/or the like.

With respect to the size of the second type of filtration catheter, alarger diameter of the catheter, at least with respect to its distalportion, provides a corresponding increase in the ability to allow bloodflow into the carotid arteries. The body of the catheter in general canbe formed from one or more biocompatible materials, including, forexample, metals, such as stainless steel or alloys, e.g., Nitinol®, orpolymers such as polyether-amide block co-polymer (PEBAX®), nylon(polyamides), polyolefins, polytetrafluoroethylene, polyesters,polyurethanes, polycarbonates, other suitable biocompatible polymers,copolymers thereof or combinations thereof. Radio-opacity can beachieved with the addition of markers, such as platinum-iridium orplatinum-tungsten or through radio-pacifiers, such as barium sulfate,bismuth trioxide, bismuth subcarbonate, powdered tungsten, powderedtantalum or the like, added to the polymer resin. The shaft in generalcomprises different sections or portions along the length of the device.The different sections or portions of the shaft can be constructed withthe same or different materials. In addition, selected sections orportions of the shaft can be formed with materials to introduce desiredstiffness/flexibility for the particular section or portion of thecatheter. For example, materials with metal wires embedded insidepolymer maybe used for polymeric sections of the shaft or in selectedsections of the shaft. Upon heating over the softening temperature ofthe polymer and subsequent cooling, the wire can become embedded withinthe polymer. Suitable wire includes, for example, stainless steel wire,Nitinol wires or alike, and the wire can be flat or rounded with anappropriate small diameter or thickness. The metal wire can addadditional mechanical strength while maintaining appropriate amounts offlexibility for the shaft of the catheter.

In some embodiments, the overall length of the second type of filtrationcatheter may be approximately 40 cm to 200 cm, in other embodiments, theoverall length may be approximately 50 cm to 180 cm, and in additionalembodiments, the overall length may be approximately 60 cm to 160 cm. Insome embodiment, the filtration catheter can be fit through anintroducer sheath, including commercially available sheaths. As aspecific example, if a 7 F introducer sheath is used, the outer diameterof the delivered portion of the filtration catheter can have an outerdiameter of no more than approximately 0.077 inches. In general, theouter diameter of the filtration catheter may be about 5 Fr to about 7Fr, in other embodiments, about 5.5 Fr to about 6.5 Fr, in additionalembodiments, about 6 Fr. A person of ordinary skill in the art willrecognize that additional ranges of the filtration catheter length anddiameter within the explicit ranges above are contemplated and arewithin the present disclosure.

A fragmentary side view illustrating proposed blood flow in a vessel 398when the filter catheter 304 is deployed is shown in FIG. 5A.Specifically, balloon 316 is deployed to contact the wall of the vessel398. Blood flow 396 in the vessel enters the distal opening 312, goesthrough conduit 314 and exits the filtration catheter 304 through theintegrated filter element 308 as filtered blood 394. The arrows in thefigures are used to indicate the direction of the blood flow. Ancillarycomponents that can be used in conjunction with the filtration catheterare shown in FIG. 5B and FIG. 5C. Specifically, an obturator 346 asshown in FIG. 5B can be used to facilitate delivery of the filtrationcatheter, and a sheath 380 with a distal opening 382 as shown in FIG. 5Ccan be used to facilitate delivery and/or retrieval of the filtrationcatheter. The obturator 346 would be placed into the main lumen 330 ofthe filtration catheter including internal lumen 318 of the integratedfilter element 308 and the conduit 314 during delivery over a guidestructure through a guide port 348 to protect the integrated filterelement 308 from damage during delivery. Obturator 346 can have a guidelumen 344. Sheath 380 can be positioned over the exterior of thefiltration catheter 304 to cover at least a portion of the filtrationcatheter during delivery and/or recovery of the filtration catheter fromthe patient to protect the filter element 308 during delivery and/or tofurther reduce the chance of any emboli escaping from the filterelements during removal and to optionally provide for the successfulapplication of suction within the lumen of the filter structure byrestricting flow into the main lumen 330 from the distal opening 312.Thus, during recovery, the sheath 380 can be advanced to cover filterelement 308. A catheter or sheath can also be used to facilitateretrieval of the independent filter element of the second type offiltration system. For example, in some embodiments a catheter can bedelivered through the lumen of the second filtration catheter along theguide structure of the independent filter element to collapse a baskettype filter element into a retrieval configuration or generally coverthe filter element if already in a retrieval configuration through themanipulation of the guide structure alone. In further embodiments, acatheter can be used to provide aspiration during the retrieval of anindependent filter, such as a FIBERNET® filter.

Occlusive Elements

The occlusive elements of either type of filtration catheters aredesigned to stop direct blood and emboli flow into the carotid arteriesand redirect the flow through an integrated filter element of thecatheters. The occlusive elements generally have an un-extended deliveryconfiguration and an extended deployed configuration. In the extendeddeployed configuration, the occlusive element has the appropriatediameter and mechanical flexibility to form contact with surroundingblood vessel to reduce or eliminate passage of blood. The balloons usedas the occlusive elements in the catheters can generally be inflatedusing saline or other appropriate fluid. In embodiments where asupported membrane is used as occlusive elements, a spring metal framecan be used as the supporting means, which can resume an extendedconfiguration upon release, and various other mechanical occlusiveelements can be used with an extended deployed configuration, ifdesired. Balloons, membranes, and the like can be formed from suitablepolymers including elastic polymers and the like. Suitable polymersinclude polyether-amide block co-polymer (PEBAX®), nylon (polyamides),polyolefins, polytetrafluoroethylene, polyesters, polyurethanes,polycarbonates or other suitable biocompatible polymers. For compliantballoons, suitable elastic polymers, such as thermoplastic elastomers,can be used to form the balloon include, for example, Pebax®(poly(ether-block-amide)), low durometer polyurethanes,styrene-butadiene copolymers, latex, polyisoprene, synthetic rubbers andthe like.

In some embodiments, a compliant balloon can have a length along thecatheter from about 2 mm to about 25 mm, in other embodiments from about3 mm to about 20 mm and in additional embodiments from about 4 mm toabout 18 mm. In general, for the first type of filtration system,because the distal balloon or occlusive element is deployed in the leftcarotid while the proximal balloon or occlusive element is deployed inthe brachiocephalic artery, the proximal balloon generally has a biggerdiameter when inflated. For example, in some embodiments, the inflatedproximal balloon or other extended proximal occlusive element can havean outer diameter from about 6 mm to about 25 mm, in some embodimentsfrom about 8 mm to about 22 mm and in further embodiments from about 9mm to about 20 mm. Similarly, the inflated distal balloon or otherextended distal occlusive device can have an outer diameter from about 4mm to about 16 mm, in some embodiments from about 5 mm to about 15 mmand in further embodiments from about 6 mm to about 16 mm. The diameterof the occlusive element for the second type of filtration catheter canbe made comparable to the proximal occlusive element of the first typeof filtration catheter for deployment in the brachiocephalic artery.Other sizes for the occlusive element can be adopted for other type ofblood vessel sizes accordingly. A person of ordinary skill in the artwill recognize that additional ranges of lengths and diameters withinthe explicit ranges above are contemplated and are within the presentdisclosure.

Filter Elements

The filter elements for either type of filtration systems are designedto allow blood to flow to the right and left carotid arteries whileentrap clinically significant emboli. The diameter of the integratedfilter element for example can be similar to the diameter of theremaining shaft of the catheter. The length of the integrated filterelement along the axis of the catheter can be selected to be largeenough to achieve a desired flow rate through the filter. However,constraints in the vessel can limit the length of the filter, and filterdesign to achieve appropriate levels of mechanical strength can becomemore complicated for longer filters. For example, due to greater flowdesired through the proximal filter of the first type of filtercatheter, the proximal filter can generally have a greater length thanthe distal filter as well as potentially a greater diameter. In general,the proximal filter can have a length from about 10 mm to about 100 mm,in some embodiments from about 20 mm to about 80 mm and in furtherembodiments from about 25 mm to about 75 mm. The distal filter can havea length from about 5 mm to about 30 mm and in further embodiments fromabout 6 mm to about 20 mm. The length of the integrated filter elementfor the second type of filtration catheter can be made comparable to theproximal filter element of the first type of filtration catheter. Otherlengths of the integrated filter element can be adopted for other typeof blood vessel sizes accordingly. A person of ordinary skill in the artwill recognize that additional ranges of filter lengths within theexplicit ranges above are contemplated and are within the presentdisclosure.

While the filter can comprise a solid membrane with drilled holes or thelike, the integrated filter elements in general can be formedeffectively from fibers, filaments, wires, and/or yarns that are weaved,braided, and/or knitted to form an approximately tubular filter element.The filter element can comprise, for example, bundles of fibers, fiberyarns, metallic wires or a combination thereof, braided at a constant orvariable pique per inch. The filter element in general is incorporatedinto the catheter structure to replace a portion of the catheter shaftso fluid from the interior of the catheter can exit the catheter throughthe filter elements while emboli is trapped or retained by theintegrated filter element. In some embodiments, the filter elements canbe designed to capture most emboli, i.e. at least about 95%, with anaverage diameter of at least about 50 micron. In some embodiments, thefilter elements may have effective pore sizes of about 30 micron toabout 600 micron, in other embodiments, about 40 micron to about 500micron, in additional embodiments about 50 micron to about 250 micron. Aperson of ordinary skill in the art will recognize that additionalranges of pore sizes within the explicit ranges above are contemplatedand are within the present disclosure.

In general, the fibers used in the filter elements can have circularcross sections or non-circular cross sections, such as an oval crosssection. In some embodiments, suitable fibers can have diameters from 5microns to about 150 microns, in further embodiments from about 7.5microns to about 125 microns, and in additional embodiments from about10 microns to about 100 microns. A person of ordinary skill in the artwill recognize that additional ranges of diameters within the explicitranges above are contemplated and are within the present disclosure. Insome embodiments, the fibers used in the filter elements comprisesurface capillary (SCF) fibers. For example, the SCF fibers can be usedtogether with other type of fibers and/or elements to provide filterelements with desired filtration property and mechanical strength. Theuse of SCF fibers can be particularly desirable for the independentfilter element of the second type of filtration system as discussedfurther below along with a more detailed discussion about properties ofSCF fibers in general. The number and thickness of metal wires can beselected to provide a desired degree of mechanical integrity to thefilter structure, and polymer fibers can be woven appropriately to takeadvantage of the structural stability provided by the metal wires. Thenumber of polymer fibers and the weave can be similarly selected toprovide a desired degree of filtration and flow through the filter. Forexample, in some embodiments, 5-50 strands of stainless steel ortitanium wire with a diameter from about 0.0005 inch to about 0.005 inchcan be used to provide support in a selected weave. As an example of thepolymer strands, 10-100 strands with 5-50 filaments per stand of 100denier to 100 denier filaments can be woven into the filter elementaround the metal wire support. Various ways can be incorporated into tothe weave to integrate the metal wires and polymer fibers based on knownweaving approaches in the art.

The selection of the composition for the fibers including the SCF fiberscan provide further flexibility to the properties of the fiber for aparticular filter element design. For example for polymeric fibers, thefiber polymer composition can modulate the hydrophobic or hydrophilicnature of the filter elements, or the polymer may elute controlledreleased drugs. Furthermore, the fibers can incorporate coatings or thelike that can further modify the fiber properties. Additionally, metalwires, such as stainless steel or alloys, e.g., Nitinol, can be used inplace of or in conjunction with the polymeric fibers to provide physicalintegrity, strength and flexibility of the filter element. Referring toFIGS. 3B and 3C, for example, the integrated filter element comprisesmetal wires 176 to provide mechanical strength to the filter element. Ingeneral the metal wires can be round, flat, oval or other shape. Thepolymer used herein generally can incorporate certain desired propertiesof medical polymers, such as established biostability, strength, andflexibility. In some embodiments, the fibers are formed from polymers,such as commercially available polyester (PET) fibers, polyetherimidefibers such as Ultem, and/or aramid fibers such as Kevlar or Nomex. Insome embodiment fibers with relatively higher temperature resistance canbe used so the fiber elements can be better integrated into the shaft ofthe device. Suitable polymers include, for example, polyamides (e.g.,nylon), polyesters (e.g., polyethylene teraphthalate),polyacetals/polyketals, polyimide, polystyrenes, polyacrylates,polylactic acid, vinyl polymers (e.g., polyethylene,polytetrafluoroethylene, polypropylene and polyvinyl chloride),polycarbonates, polyurethanes, poly dimethyl siloxanes, celluloseacetates, polymethyl methacrylates, polyether ether ketones, ethylenevinyl acetates, polysulfones, nitrocelluloses, similar copolymers andmixtures thereof. In some embodiments, radiopaque fibers including metalwires can be used in the filter element. For example the use ofradiopaque polymer fibers in filter elements is discussed in thepublished U.S. patent application 2007/0172526A to Galdonik et al.,entitled “Radiopaque Fibers and Filtration Matrices,” incorporatedherein by reference.

Surface Capillary Fibers

Surface capillary fibers (SCFs) are known to provide desirablefiltration properties in embolic protection devices for use in arteries.The formation of vascular filters with an unwoven mat of SCF fibers forexample is described in U.S. Pat. No. 7,879,062 to Galdonik et al.,entitled “Fiber Based Embolism Protection Device,” incorporated hereinby reference. Embolism protection devices formed with surface capillaryfibers in commercial embodiments such as FiberNet® from Medtronic, Inc.provide excellent filtering properties and are discussed in more detailbelow.

A schematic cross section of an embodiment of a surface capillary fiber480 is shown in FIG. 5D, along with a cross section of two contrastinground fibers 482 and 484 shown in FIGS. 5E and 5F respectively. SCFfibers are characterized by surface channels or capillaries 486 formedalong the surface of the fiber. Surface capillaries are characterized byhaving a portion of the capillary exposed at the surface of the fiberalong the length of the fiber. The surface capillaries result insignificant increase in the surface area of the fibers relative tofibers with a smooth surface and the same diameter. The surfacecapillaries generally run along the length of the fiber. An SCF fibercan have surface channels that essentially make up a large fraction ofthe bulk of the fiber such that little if any of the interior mass ofthe fiber is not associated with walls of one or more surfacecapillaries. The surface channels of the SCF can impart excellent fluidtransfer properties. In addition, the surface channels can house atherapeutic agent if desired. These fibers can help facilitate excellentflow maintenance (even after embolic entrapment) and entrapment of verysmall particles (˜40 microns). The SCF fiber substrate can be formedwith a relatively complex cross-sectional geometry. Generally, the SCFfibers are formed from polymers, such as organic polymers, which can beformed into SCF fibers by extrusion. Suitable approaches for themanufacture of the SCF are described in, for example, U.S. Pat. No.5,200,248 to Thompson et al., entitled “Open Capillary Structures,Improved Process For Making Channel Structures And Extrusion Die For UseTherein,” incorporated herein by reference. Geometries of the crosssection of the SCF can be selected to be particularly advantageous for aparticular application. Suitable fiber geometries include, for example,4DG™ fibers ranging from about 1 denier to about 1000 denier in size(Fiber Innovation Technology, Inc., Johnson City, Tenn.) but would alsoinclude other fiber geometries.

FIBERNET type of filters has been shown to be particularly effective incarotid artery embolic protection as discussed in the U.S. Pat. No.7,879,062 cited above. An embodiment of the FIBERNET type of filterdevice 400 is illustrated in FIG. 5G. The filter device 400 can comprisea guide structure 402 that comprises an overtube 406, a corewire 408with a proximal end 410, and a filter element 420. An actuation tool forthe filter is described further in U.S. Pat. No. 8,070,694 to Galdoniket al., entitled “Fiber Based Medical Devices and Aspiration Catheters,”incorporated herein by reference. The overtube 406 can have a taperedsection 412 with a wire coil 414 adjacent tapered section 412. Corewire408 can be covered with a coil 416 at its distal end. In thisembodiment, the filter element 420 generally comprises a bundle of SCFfibers 404 that is shown in a flared up configuration. The flared fibers404 is believed to form a porous three dimensional filtration matrixthat comprises a plurality of effective pores that are sized to trapemboli. The filter device can be used in conjunction with the secondtype of filtration catheter to form embodiments of second type offiltration system that are particularly suitable for embolic protectionduring heart surgeries. An embodiment of the second type of filtrationsystem combining the filtration catheter 304 of FIG. 4A with theFIBERNET type of filter device 400 illustrated in FIG. 5G is shown anddiscussed below in FIG. 8B.

Specific Filtration Catheter Design

A specific design of the first type of filtration catheter with distalports and various cross sections of the shaft are illustrated in FIGS.6, 6A-6G. Specifically, FIG. 6 is a fragmentary side view of afiltration catheter 500 according to one embodiment of the first type offiltration system. Enlarged cross sectional views of the catheter 500along the A-A, B-B, C-C, D-D, and E-E lines are illustrated in FIGS.6A-6E respectively. As shown in FIG. 6, the filtration catheter 500comprises a distal filter element 502, a proximal filter element 508, aninflow opening 512 on the shaft between the two filter elements, a mainlumen 530, and a distal port 522. Both the distal filter element 502 andthe proximal filer element 508 are a part of the catheter that isintegrated with the rest of catheter body. The proximal filter element508 can be longer than the distal filter element 502 to accommodate thelarger blood flow into the brachiocephalic artery. For example, in thisdevice the distal filter element 502 is about 20 mm in length while theproximal filter element 508 is about 30 mm in length. The filtrationcatheter 500 additionally comprises a proximal balloon 516 and a distalballoon 518 that can extend from the exterior of the catheter. Theproximal balloon 516 is positioned between the inflow opening 512 andthe proximal filter element 508, and the distal balloon 518 ispositioned between the inflow opening 512 and the distal filter element502. The distance between the proximal balloon 516 and the distalballoon 518 in general need to be long enough to span between and toaccess the entrances of the brachiocephalic artery and the left carotidartery. The filtration catheter 500 additionally employs radio opaquebands 506 to facilitate visualization during the delivery and placementof the device, and the number of radiopaque marker bands and theirlocation can be selected as desired to facilitate the procedure.

Cross sectional views along the lines A-A to E-E of the filtrationcatheter reveal internal structure of the catheter shaft. As shown inFIGS. 6A and 6B, the filtration catheter 500 comprises a main lumen 530that houses a balloon lumen 524 and a balloon lumen 526 that areparallel to each other. The view in FIG. 6C indicates that the cathetercomprises only one balloon lumen 526 and with the other balloon lumen524 terminated after connection with the interior of proximal balloon516. The view in FIG. 6D shows the inflow opening 512 on the catheterwith only one balloon lumen 526 extending through this part of theshaft. This part of main lumen 530 can also be referred to as conduit.The view in FIG. 6E indicates the tapered tip portion of the filtrationcatheter with a distal guide port 522. The filtration catheter 500illustrated does not have a separate guidewire lumen. In addition toproviding fluid communication between different parts of the catheter,The main lumen 530 also serves as a guidewire lumen. The filtrationcatheter therefore can be tracked directly through the distal guide port522 on a guidewire. FIG. 6F shows fitting or connector 550 with theproximal ports 538, 540, and 542 that can be connected to the filtrationcatheter 500 via a connector 544. In terms of usage, proximal port 540for example can provide exit for a guidewire or alike and proximal ports538 and 542 can provide inflation or deflation of balloons and optionalconnection to an aspiration device, such as a syringe or the like, toprovide aspiration of the filter element(s) through the main lumen ifdesired. FIG. 6G is a plan view of connector 550 of FIG. 6F looking in aproximal direction along the longitudinal axis with all three ports 538,540, and 542 aligned in the same plain as that of connector 544.

Use of Filtration Systems for Embolic Protection

The filtration systems described herein can be effectively used forembolic protection of carotid arteries during and/or followingprocedures on the heart. In particular, the filtration systems describedherein can be used to provide embolic protection during endovascularcardiac procedures, such as procedures performed in or around the leftatrium and left ventricle of the heart, although the filtration systemsmay also be useful for procedures on the heart with an approach throughthe patient's chest. Some procedures may involve an endovascularapproach to the heart to accomplish certain steps of the procedure andless invasive approaches through the patient's chest for other aspectsof the procedure, such as providing cardiopulmonary bypass. Theprocedures on the heart can result in emboli that can flow from theaorta and then for circulation to other parts of the body. While embolican be undesirable in any vessel, the circulation of emboli into thecarotid arteries, and in particular the internal carotid arteries, canresult in the flow to the patient's brain where the emboli can causestrokes or other adverse consequences. Therefore, it is very desirableto filter emboli from the flow into the internal carotid arteries. Thus,in some embodiments, filter elements associated with the filtrationsystems described herein can be placed so that emboli are removed fromflow into the carotid arteries without removing emboli from flow throughthe descending aorta and/or one or both of the subclavian arteries whereemboli generally may not present a significant concern. When the riskfor emboli formation is reduced or eliminated, filtrations systems alongwith the filter elements may be safely withdrawn from the patient.

Emboli can be released into the blood flow from various procedures onthe heart. In particular, heart valve replacement involves significantmanipulations of the heart tissue and can be associated with a risk ofemboli generation. Other heart procedures include, for example, heartvalve repair procedures. Emboli that are generated within or near theleft heart chambers may be released into the aorta upon resumption ofheart pumping if cardiopulmonary bypass is used. Emboli released intothe ascending aorta can flow downstream and may generate a risk ofemboli within the carotid arteries. In some embodiments, heartprocedures of interest include, for example, endovascular procedures inwhich instruments are delivered in a percutaneous format up an artery,such as the femoral artery or a subclavian artery to reach the heart.

While the filtering procedures described herein are applicable forprotection during various heart procedures, the procedures can beadvantageously used in conjunction with performing percutaneous heartvalve replacement. Generally, a percutaneous procedure to replace theaortic valve comprises delivery of a prosthetic heart valve through apatient's peripheral vasculature to an area at or near the valve root,such as the aortic annulus or the mitral valve annulus. The valvereplacement procedure may comprise the excising of the native valve,although in some embodiments, the replacement valve can be placed withinthe native valve without removing the native valve. The patient may beplaced on cardiopulmonary bypass to provide for oxygenated blood flowwhile the valve is being replaced. The prosthetic heart valve can bedelivered as a single unit or it can be delivered as a plurality ofsub-units and assembled in the patient's body. The procedure furthercomprises implantation of the prosthesis in the desired location. Wherethe prosthesis comprises a plurality of sub-units, the components of theprosthetic valve can be assembled prior to implantation and/or assembledwithin the patient.

In some embodiments, a method for performing such a percutaneous valvereplacement procedure comprises the delivery of a compressibleprosthetic aortic valve comprising a tissue engaging base, designed tohold the prosthesis in place at or near the annulus of the native valve,and a leaflet element, designed to function as a valve. The prosthesiscan comprise a plastically deformable structure that is designed toretain its configuration when crimped for delivery. The prosthesis canbe affixed to a delivery catheter comprising, concentrically, an outersheath, an optional push catheter, and a balloon catheter, and theprosthesis can be attached to the balloon catheter such that when theballoon is inflated, the prosthesis adopts its expanded configuration.The catheter can be tracked into the region of the valve annulus from avariety of peripheral arteries or veins, for example, the left femoralartery or right femoral artery. The outer sheath can be tracked into theascending aorta from a peripheral artery, for example, using a varietyof standard techniques such as with the use of a guidewire. When theprosthesis reaches the desired location within the aortic annulus, theouter sheath is pulled back, exposing the prosthetic valve element. Inappropriate embodiments, the balloon is then expanded, placing theprosthesis in its expanded configuration. The balloon is then deflatedand the delivery structure removed. For alternative embodiments in whichthe prosthesis has a self-expanding design, simply removing theprosthesis from the outer sheath can induce an expanded configuration.Further discussion on this heart valve replacement procedure as well asalternative embodiments can be found in U.S. Pat. No. 6,454,799 toSchreck, entitled “Minimally-Invasive Heart Valves and Methods of Use,”incorporated herein by reference. Heart valve prostheses that can beplaced in an aortic valve position or mitral valve positions with orwithout removing the native valve are described further in U.S. Pat. No.7,329,278 to Seguin et al., entitled “Prosthetic Valve for TransluminalDelivery,” incorporated herein by reference.

The filtration systems described herein can be used to provide embolicprotection for selected vessels during a particular heart procedure. Thefiltration system is generally guided into position through a selectedartery, e.g., brachial artery or radial artery in the arm leading to thebrachiocephalic artery. The various filtration system designs describedabove are generally designed for delivery through a right subclavianartery to access the brachiocephalic artery. In general, the filtrationsystem described herein is designed appropriately following deploymentto avoid interfering with any tools used to perform the heart procedure.Specifically, the deployment of the first type of filtration systeminvolves deployment of the occlusive elements so the blood flow can beredirected and filtered. The deployment of the second type of filtrationsystem involves both the deployment of the occlusive element as well asthe delivery of the filter device and deployment of the independentfilter element of the filter device.

In general, the filtration system can be deployed at a selected time,which generally is prior to the time at which there is a significantrisk for emboli generation. The appropriate timing for deployment of thefiltration system generally depends significantly on the nature of theheart procedure. In some embodiments, if the filtration system does notinterfere with any of the heart procedure steps or instruments, thefiltration system can be deployed prior to any significant portions ofthe heart procedure. If good flow is maintained across the filterelements during the whole procedure, the filtration system can be leftin place for a significant period of time without any adverse effects.In some embodiments, some steps of the heart procedure may be performedprior to the placement of the filtration system. It may be advantageousto deliver and deploy the filtration system at a later stage if theearly steps of the heart procedure do not generate a significant embolicrisk and/or if the early steps of the heart procedure could determinethat the continuation of the heart procedure is contraindicated. Thefiltration system though is generally delivered and deployed prior toany significant risk of emboli generation within the aorta.

After the significant risk for emboli generation has passed, thefiltration system can be removed from the patient. In some embodiments,the filtration system can be removed after the heart procedure hascompleted. It may be desirable to continue filtration until aftercardiopulmonary bypass has been ended and the natural heart function hasbeen restored for a period of time. If some steps of heart procedure donot generate a significant risk from emboli or if the filtration systemmay interfere with some steps of the heart procedure, the filtrationsystem may be removed prior to completing all of the steps of the heartprocedure. Furthermore, the filtration system can be removed at onestage in the procedure and replaced with another filtration system at alater stage of the procedure.

Generally, to effectuate the removal of the first type of filtrationcatheter from the patient, the occlusive elements of the catheter can becollapsed to a recovery configuration and the filtration catheterremoved from the vessel. The steps to accomplish these objectives dependsignificantly on the design of the occlusive elements and/or the filterdevice. For example, the occlusive elements may be collapsed with asheath or the like to mechanically collapse the occlusive elements.Balloons can be placed in a recovery configuration by deflating theballoons.

The removal of the second type of filtration system involves the removalof the filter device along with the removal of the filtration catheter.In general, the order of removal of the filtration catheter and theindependent filter element can be performed for convenience as well asto reduce the chance of releasing any emboli. For example, thefiltration catheter can be removed first to make it easier to introducea separate catheter to facilitate removal of the independent filterelement. On the other hand, if the filtration catheter, optionallycovered with a sheath or the like, is used to facilitate removal of theindependent filter catheter, the two components can be removed together.Thus, various procedures can be used for safe removal of the second typeof filtration system from the patient.

Regardless of the design of the occlusive elements, a sheath can be usedto facilitate recovery of the filter catheter to cover one or bothfilters and/or to cover the inflow opening for the first type offiltration system. Catheter or sheath may be used to facilitate thecollapsing or simply covering of the independent filter element in thesecond type of filtration system. In some embodiments, suction may beapplied during some portion of the process to facilitate the removal ofthe filtration system from the vessel. If suction is applied during theretrieval of the first type of filtration system, the inflow openingmaybe covered with a sheath so suction can be transmitted effectively toboth filter elements. If suction is applied during the retrieval of theindependent filter element of the second type of filtration system, asheath maybe used to cover the filter element to avoid release of thecaptured emboli. The use of suction for the recovery of a filter devicehas been discussed for example in published U.S. Pat. No. 8,021,351 toBoldenow et al., entitled “Tracking Aspiration Catheter,” and publishedU.S. patent application 2005/0277976 to Galdonik et al., entitled“Emboli Filter Export System,” both of which are incorporated herein byreference.

The procedures described herein generally involve access to thepatient's vascular system through a small hole. Generally, the selectedvessel can be accessed, for example, with conventional tools, such asintroducers, cannula and the like. Hemostatic valves, Luer fittings,other fittings and the like can be used to reduce bleeding from thepatient during the procedure. The fittings provide for the introductionand removal of various devices at appropriate times in the procedure.

FIGS. 7A-7L illustrates an example of a process of using a first type offiltration catheter 610 during an endovascular procedure. Referring toFIG. 7A, a guide wire 620 can be delivered from the right subclavianartery 662, past the entrance of the right carotid artery 668, along anaortic arch 660 through the brachiocephalic artery 664, and into theleft carotid artery 666. A separate guide structure 624 can be deliveredinto the aortic arch to facilitate performance of a procedure on theheart. As shown in FIG. 7A, there is no interference between the guidestructure 624 and the guide wire 620. Referring to FIG. 7B, filtrationcatheter 610 with a tapered distal tip 628 is delivered along theguidewire 620 while separate guide structure 624 is deployed in theaorta to facilitate a procedure on or near the heart. A distal filterelement 602 is integrated into the shaft and connected proximally to thetapered tip 628. Distal balloon 618 is shown in a low profile deliveryconfiguration with two radio opaque marker bands 630 indicating theboundaries of the balloon. Natural blood flow from aorta to thesurrounding vessels is indicated by the small arrows in FIG. 7B.

Referring to FIG. 7C, filtration catheter 610 is advanced along theguidewire 620 to position the distal filter element 602 and the distalballoon 618 into the left carotid artery 666, having the inflow opening612 placed along the aortic arch, and the proximal balloon 616 and atleast part of the proximal filter element 608 placed inside thebrachiocephalic artery 664. Filtration catheter 610 is positioned toplace the distal balloon 616 inside the left carotid artery 666 whilehaving the proximal balloon 616 placed inside the brachiocephalic artery664 to help properly position the inflow opening 612 inside the aorticarch, while having at least a portion of the proximal filter element 608placed inside the brachiocephalic artery and the distal filter element602 placed inside the left carotid. To help visualize the placement ofthe catheter during the delivery process, the distal balloon 618 isflanked by two radiopaque marker bands 630 while the proximal balloon616 is flanked by two radiopaque marker bands 632, so the positions ofthe balloons will be visible with x-rays during the operation. Theproximal balloon 616 is shown to be visibly longer (larger) than thedistal balloon 618 while the proximal filter element 608 is shown to bevisibly longer than the distal filter element 602.

Referring to FIG. 7D, the distal balloon 618 is inflated to block directblood flow into the left carotid artery 666. As shown by the arrows,while the natural blood flow is maintained in the aortic arch andbrachiocephalic artery, some blood flow enters the inflow opening 612,flows through a distal conduit 614 b and exits the distal filter element602. In contrast, because the proximal balloon 616 is not yet inflated,the natural blood flow into brachiocephalic artery 664 is not blockedand re-directed and still flows freely without being filtered, bypassing the filtration catheter 610 into the right carotid artery 668.

Referring to FIG. 7E, in addition to the distal balloon 618, theproximal balloon 616 is also inflated to block direct blood flow intothe right carotid artery 668. As shown by the arrows, while the naturalblood flow is maintained in the aortic arch 660, some blood flow entersthe inflow opening 612, flows through a proximal conduit 614 a and thedistal conduit 614 b and exits the proximal filter element 608 and thedistal filter element 602 into the right carotid and the left carotidarteries 668 and 666 respectively. Because both the distal balloon andthe proximal balloon elements are inflated and contact with the vesselwalls, the filtration catheter 610 is relatively stationary inside theaortic arch 660, providing continuous filtration of the blood flowingfrom the aorta to the carotid arteries.

Referring to FIG. 7F, a treatment catheter 626 is delivered over theguide structure 624 to the aortic arch 660. As shown in FIG. 7F, thereis no interference between the treatment catheter 626 and the filtrationcatheter 610. Referring to FIG. 7G, emboli 634 are generated by thetreatment catheter 626 and enter the inflow opening 612 of thefiltration catheter 610 along with the blood flow. Filtered blood exitsthe filter elements while the emboli are trapped inside the filterelements. FIG. 7H shows an enlarged section of filter element withinterwoven polymer fibers 604 and diamond patterned metal filaments 606.Emboli 634 are shown to be captured by the filter element in theenlarged view.

FIGS. 7I-7L illustrates retrieval process of the filtration catheter610. Specifically, referring FIG. 7I, the treatment catheter 626 isretrieved from the aorta while the filtration catheter 610 is stilldeployed performing the filtration protection of carotid arteries. Oncethe treatment catheter is completely removed, the proximal balloon 616is deflated as shown in FIG. 7J followed by the deflation of distalballoon 618 as shown in FIG. 7K, restoring natural blood flow intobrachiocephalic artery 664 and left carotid artery 666 sequentially.Once both balloons are deflated, the filtration structure 610 isretrieved from the aorta as shown in FIG. 7L.

FIG. 8A is a schematic diagram illustrating the second type offiltration system 300 of FIGS. 4A-4G placed inside the aortic arch 360by way of the right subclavian artery 362, with the proximal portion 336of the filtration system placed outside the patient with shaft 306extending into the patient. In some embodiment, once the filtrationcatheter 304 is successfully delivered and properly placed inside thebrachiocephalic artery 364, the compliant balloon 316 can be inflated toanchor the filtration catheter 304 inside the brachiocephalic artery364. Filter device 350 can be delivered through the main lumen 330 ofthe anchored filtration catheter 304 to enter the left carotid artery366 through the aortic arch 360. As shown in FIG. 8A, when properlyplaced, distal opening 312 at the distal tip 322 of the filtrationcatheter 304 is located close to the entrance of the brachiocephalicartery 364, with the guide structure 320 of the filter device spanningbetween the entrances of the left carotid artery 366 and thebrachiocephalic artery 364. The integrated filter element 308 and theballoon 316 are placed inside the brachiocephalic artery 364 with theintegrated filter element 308 positioned proximally beyond the balloon316. The independent filter element 352 with the distal tip 358 andstrut 356 is placed inside the left carotid artery 366 with thefiltration structure 354 of the independent filter element 352 deployedto contact the wall of the left carotid artery 366 to trap emboli. Thefiltration catheter and the filter device shown in FIG. 8A represent oneembodiment of the second type of filtration system during an emboliprotection procedure.

During the operation, on the right carotid artery 370 side, blood flow368 in the aorta 360 is redirected by the distal balloon 316 to enterthe distal opening 312 of the filtration catheter 304, travels throughthe conduit 314, and exit as filtered blood 372 through the integratedfilter element 308 to enter into the right carotid artery 370. On theleft carotid artery 366 side, blood flow 368 in the aorta 360 travelsthrough the basket 354 of the independent filter element 352, and exitsas filtered blood 374 to enter into the left carotid artery 366. Thedirection of the flow of the blood is indicated by black arrows in FIG.8A.

FIG. 8B shows an alternative rapid exchange embodiment of filtrationsystem 450 placed inside aortic arch 360 by way of the right subclavianartery 362, with a proximal portion 436 positioned outside the patient.Filtration catheter 454 comprises a rapid exchange guide wire port 452that guide structure 430 of filter device 460 extends through. Proximalportion 436 may or may not comprise a main lumen if it is desirable tohave access to the flow, such as for the delivery of a drug, contrastdye or aspiration. During delivery, the filtration catheter 454 can bepre-loaded with a filter device 460 and then the entire filtrationsystem 450 can be delivered together, with the relative positions of theelements adjust as appropriate during delivery. The rest of theprocedure should be very similar to the embodiment described in FIG. 8A,with the only difference being the rapid exchange configuration of theguide structure 430 relative to filtration catheter 454.

As shown in FIG. 8B, when properly placed, distal opening 464 offiltration catheter 454 is located close to the entrance of thebrachiocephalic artery 364, with guide structure 430 of filter device460 spanning between the entrances of the left carotid artery 366 andthe brachiocephalic artery 364. Integrated filter element 428 andballoon 426 are positioned inside the brachiocephalic artery 364 withintegrated filter element 462 positioned proximally relative to balloon426. Alternatively, filter device 460 with guide structure 430 can bedelivered and positioned inside aortic arch 360 and into left carotidartery 366 through brachiocephalic artery 364. With independent filterelement 462 of filter device 460 successfully delivered and properlyplaced inside left carotid artery 366, filtration catheter 454 can thenbe delivered over guide structure 430 that extends through rapidexchange port 452. In general, the rapid exchange catheter embodimentscan be designed with the guidewire extending through a main catheterlumen 466 or a distinct guidewire lumen. While shown in FIG. 8B withrapid exchange port 452 positioned in a proximal position relative toproximal filter 428, rapid exchange port 452 can be positioned at anypoint proximal to proximal occlusive element 426. Arrows 478 is used toindicate blood flow in the aorta that enters the inflow opening 464 ofthe filtration catheter 454, travels through the conduit 468 and exitsas filtered blood flow 472 through integrated filter element 428 toenter into right carotid artery 370. On the left carotid side, arrows478 are used to indicate blood flow in the aorta that enters leftcarotid artery 366 and filtered by independent filter element 462 andexit as filtered blood flow 474 into left carotid artery 366.

FIG. 8C is a schematic diagram illustrating another embodiment of thesecond type of filtration system with filtration catheter 304 used inconjunction with a filter device 400 in the vessels of a patient. Thefiltration catheter 304 can be delivered through right subclavian artery362 and positioned similarly as described above while the proximalportion 336 remains outside the patient. The compliant balloon 316 canthen be inflated to anchor the filtration catheter 304 inside thebrachiocephalic artery 364. Filter device 400 can then be deliveredthrough main lumen 330 of the anchored filtration catheter 304 to enterleft carotid artery 366 through the aortic arch 360. As shown in FIG.8C, when properly placed, the guide structure 402 of filter device 400spans between the entrances of the left carotid artery 366 and thebrachiocephalic artery 364. The independent filter element 420 with thedistal tip 416 is placed inside the left carotid artery 366 with thefibers 404 of the independent filter element 420 deployed to contact thewall of the left carotid artery 366 to provide a porous threedimensional filtration matrix that comprises a plurality of pores thatare sized to trap emboli. The filtration catheter and the filter deviceshown in FIG. 8C represent another embodiment of the second type offiltration system during an emboli protection procedure. Arrows 378 isused to indicate blood flow in the aorta that enters the inflow opening312 at the distal tip 322 of the filtration catheter 304, travelsthrough the conduit 314 and exits as filtered blood flow 375 through theintegrated filter element 308 to enter into the right carotid artery370. On the left carotid side, arrows 378 is used to indicate blood flowin the aorta that enters left carotid artery 366 and filtered by theindependent filter element 420 and exit as filtered blood flow 377 intothe left carotid artery 366. As shown in FIGS. 8A-C, the deployedfiltration system occupies a small portion of the space inside theaortic arch with a portion of the guide structure, leaving the rest ofthe space for procedures, such as heart valve replacement or otherprocedures, e.g., endovascular procedures, on or in the vicinity of theheart. Because the filter element is an integral part of the filtrationcatheter, no deployment or collapse of the filter element associatedwith regular filters is involved. After the completion of the operation,the filter device can be retracted inside the filtration catheter andthe entire system can be simply removed with the emboli trapped insidethe independent filter element as well as the conduit or within thebraids or waves of the fibers, although in other embodiments, a separateretrieval catheter, aspiration catheter or the like can be used inaddition to or as an alternative to the use of the filtration catheterto facilitate removal of the independent filter. During recovery, acatheter and/or sheath can be used to retrieve the independent filterelement of a filtration system as an alternative or in addition to thefiltration catheter or other retrieval tools. For example, as shown inFIG. 8C, a catheter 392 can be delivered through the lumen of thefiltration catheter 304 along the guide structure 402 of the independentfilter element 420 to collapse the fiber bundles 404 into a retrievalconfiguration or generally cover the filter element if already in aretrieval configuration through the manipulation of the guide structure402 alone. Suction can additionally be applied through the catheter 392to prevent the release of emboli during the retrieval process. The useof suction for the recovery of a filter device has been discussed forexample in U.S. Pat. No. 8,021,351 to Boldenow et al., entitled“Tracking Aspiration Catheter,” and published U.S. patent application2005/0277976 to Galdonik et al., entitled “Emboli Filter Export System,”both of which are incorporated herein by reference.

Examples of devices of the first and the second type filter systems areconstructed based on the disclosure herein. The examples of devices werethen placed inside glass model of aortic arch to simulate bloodfiltration/emboli capturing process in an actual aorta. FIG. 9A is aphoto of a first type of filtration catheter 700 placed inside a glassmodel of aortic arch 760 by way of the model right subclavian artery762, showing the inflated proximal balloon 716 inside thebrachiocephalic artery 764 and the inflated distal balloon 718 insidethe left carotid artery 766 and guidewire 720 extending from the distalportion of the catheter. Fluid mimicking blood with emboli is pumped tocirculate the glass model mimicking the blood flow condition in anactual aorta. As indicated by blank arrows in FIG. 9A, blood with embolienters into the inflow opening 712, is filtered by the filter elements708 and 702 and enters into the carotid arteries 768 and 766respectively. FIG. 9B shows a photo of a section of filter element withemboli 772 trapped inside the interwoven fibers 704. The enlargedsection of filter element also reveals diamond patterned metal wires orfilaments 776 integrated into the interwoven fibers 704 of the filterelement to provide structural integrity for the filter element.

FIG. 10A is a photo of an embodiment of a second type of filtrationsystem 800 placed inside a glass model of aortic arch 860 by way of themodel right subclavian artery 862, showing the filtration catheter 806is anchored by the inflated balloon 816 inside the brachiocephalicartery 864 and the deployed independent filter element 802 inside theleft carotid artery 866 and guide structure 820 spanning the aortic arch860. The independent filter element 802 attached to the guide structure820 is delivered through the filtration catheter 806. The filter element802 is shown to have a basket type of structure formed with metal meshwith the opening of the basket facing the aorta. Fluid mimicking bloodwith emboli indicated by arrows is pumped to circulate the glass modelmimicking the blood flow condition in an actual aorta. As indicated byarrows in FIG. 10A, on the brachiocephalic artery 864 side, blood withemboli enters into the distal inflow opening 812 of the filtrationcatheter 806, is filtered by the filter element 808 and enters into theright carotid artery 868. On the left carotid artery 866 side, bloodwith emboli is filtered by basket mesh of the independent filter element802, and enters into the left carotid artery 866. FIG. 10B shows photosof a section of the integrated filter element 808 with emboli 872trapped inside the interwoven fibers 804. The enlarged interwoven fibersalso reveal diamond patterned metal wires or filaments 876 integratedinto the interwoven fibers 804 of the filter element to providestructural integrity for the filter element.

Performance

The devices described herein can be configured to trap a substantialmajority of emboli or particulates while maintain blood flow through thefilter elements into the carotid arteries. The materials and structureof the device can be selected to have porosity that would allow passageof blood components, such as white blood cells (about 7-20 microns), redblood cells (8-9 microns) and platelets (2-4 microns), yet collectsemboli. The filters described herein are generally designed to trap asubstantial majority of emboli with an average diameter of at least 100microns. A substantial majority of particulates can be considered to beat least about 95 percent and in further embodiments at least about 99.5percent of all the particulates flowed through. In some embodiment, thespeed and volume of blood flow through the filter elements aresubstantially unchanged compared to without filtration. In someembodiments, the blood flow through the filter elements maintains atleast 50% of the original unfiltered blood flow in volume per unit time,in other embodiments, at least 75%, in additional embodiments at least85% relative to the natural flow through the respective vessel. A personof ordinary skill in the art will recognize that additional ranges ofparticulate trapping and percentage of flow maintained within theexplicit ranges above are contemplated and are within the presentdisclosure.

Sterilization and Packaging

The medical devices described herein are generally packaged in sterilecontainers for distribution to medical professionals for use. Thearticles can be sterilized using various approaches, such as electronbeam irradiation, gamma irradiation, ultraviolet irradiation, chemicalsterilization, and/or the use of sterile manufacturing and packagingprocedures. The articles can be labeled, for example with an appropriatedate through which the article is expected to remain in fully functionalcondition. The components can be packaged individually or together.Various devices described herein can be packaged together in a kit forconvenience. The kit can further include, for example, labeling withinstruction for use and/or warnings, such as information specified forinclusion by the Food and Drug administration. Such labeling can be onthe outside of the package and/or on separate paper within the package.In general, the filtration systems disclosed herein are for single use.

The embodiments above are intended to be illustrative and not limiting.Additional embodiments are within the claims. In addition, although thepresent invention has been described with reference to particularembodiments, those skilled in the art will recognize that changes can bemade in form and detail without departing from the spirit and scope ofthe invention. Any incorporation by reference of documents above islimited such that no subject matter is incorporated that is contrary tothe explicit disclosure herein.

What is claimed is:
 1. A filtration system comprising: a biocompatiblefiltration catheter comprising: a shaft having a balloon lumen, aproximal end and a distal end; a proximal port in fluid communicationwith the balloon lumen and connected to the proximal end of the shaft;an integrated filter element having an inner flow lumen integrated aspart of a wall of the catheter at or near the distal end of the shaft,wherein the integrated filter element provides for fluid flow out fromthe catheter interior; a distal section extending in a distalorientation from the integrated filter element and having a distalopening, wherein a tubular portion of the balloon lumen extends alongthe integrated filter element through the inner flow lumen from theshaft to the distal section; a balloon having an interior in fluidcommunication with the balloon lumen and that is associated with anexterior of the distal section at or near the distal end of the distalsection that can extend radially outward from the exterior of and aroundthe circumference of the shaft; and a conduit extending within thedistal section from the distal opening to the inner flow lumen of theintegrated filter element to provide fluid communication between thedistal opening and the integrated filter element; and a filter devicecomprising a guide structure and an independent filter element supportedby the guide structure, wherein the filtration catheter comprises acentral lumen that is suitable for the delivery of the independentfilter element mounted on the guide structure through the distal openingof the shaft.
 2. The filtration system of claim 1 wherein theindependent filter element comprises surface capillary fibers having afirst configuration in a bundle with a low profile configuration and anextended configuration with the fibers flaring outward from the guidestructure, wherein the guide structure comprises a corewire and anovertube with the corewire extending through a lumen of the overtube,and wherein the relative movement of the corewire and the overtubetransitions the fibers from the low profile configuration to theextended configuration.
 3. The filtration system of claim 1 wherein theindependent filter element comprises a filter basket.
 4. The filtrationsystem of claim 3 wherein the filter basket comprises an opening intothe filter basket oriented toward the proximal end of the guidestructure.
 5. The filtration system of claim 4 wherein the filter basketcomprises a strut configures to collapse the filter to a recoveryconfiguration with the advancement of a retrieval catheter.
 6. Thefiltration system of claim 4 wherein the filter basket comprises adistal tip extending beyond the distal end of the filter basket.
 7. Thefiltration system of claim 1 further comprising an aspiration catheterwith dimension providing for placement over the guide structure anddelivery through the lumen of the filtration catheter.
 8. The filtrationsystem of claim 1 wherein the integrated filter element comprisesinterwoven fibers.
 9. The filtration system of claim 8 wherein theinterwoven fibers further comprises metal filaments.
 10. The filtrationsystem of claim 8 wherein the interwoven fibers further comprisessurface capillary fibers.
 11. The filtration system of claim 8 whereinthe interwoven fibers have a diameter from 5 microns to about 150microns.
 12. The filtration system of claim 1 wherein the integratedfilter element having a length from about 10 mm to about 70 mm.
 13. Thefiltration system of claim 1 wherein the integrated filter element haspore sizes of about 50 micron to about 500 micron.
 14. The filtrationsystem of claim 1 wherein the shaft comprises an outer diameter andwherein the integrated filter element comprises an outer diameterapproximately the same as the outer diameter of the shaft and whereinthe integrated filter element has structural stability.
 15. Thefiltration system of claim 1 wherein the balloon has an extendedconfiguration with a diameter suitable to occlude a humanbrachiocephalic artery.
 16. The filtration system of claim 1 wherein theballoon comprises a compliant deformable material connected to the shaftto provide for inflation of the balloon.
 17. The filtration system ofclaim 1 wherein the catheter has a diameter between about 5 Fr to about7 Fr.
 18. The filtration system of claim 1 further comprising a sheathslidably positioned over the catheter having a configuration extended ina distal direction relative to the catheter covering the integratedfilter element.